TY  - JOUR
AU  - Ćorović, Marija
AU  - Mihailović, Mladen
AU  - Banjanac, Katarina
AU  - Carević, Milica
AU  - Milivojević, Ana
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3655
AB  - The aim of this study was to develop simple and efficient method for immobilization of Candida antarctica lipase B onto hydrophobic anion exchange resin Purolite(A (R)) MN102 and to apply immobilized catalyst for the enzymatic synthesis of two valuable esters-isoamyl acetate and l-ascorbyl oleate. At optimized conditions (1 M phosphate buffer pH = 7, 7 h at 25 A degrees C, and 18.75 mg of offered proteins g(-1) of support), immobilized lipase with hydrolytic activity of 888.4 p-nitrophenyl butyrate units g(-1) was obtained. Afterwards, preparation was applied for the solvent-free synthesis of isoamyl acetate from triacetin and isoamyl alcohol. At 75 A degrees C, 1 M of isoamyl alcohol, and 6 mg ml(-1) of enzyme 100 % yield was achieved in 6 h, while at prolonged reaction times, complete conversion was enabled even at lower temperatures, lower lipase loadings, and higher substrate concentrations. After 15 consecutive reuses (60 h), activity of catalyst dropped to 50 % of its initial value and total amount of 1.31 mol (170.55 g) of ester with 1 g of biocatalyst was produced. Even higher operational stability of lipase (25 % loss of activity in 200 h) was observed in the synthesis of l-ascorbyl oleate performed in organic solvent (t-butanol). Multiple use of one batch of immobilized biocatalyst in both cases led to a significant process cost reduction and substantial increment of corresponding productivities.
PB  - Springer, New York
T2  - Bioprocess and Biosystems Engineering
T1  - Immobilization of Candida antarctica lipase B onto Purolite(A (R)) MN102 and its application in solvent-free and organic media esterification
EP  - 34
IS  - 1
SP  - 23
VL  - 40
DO  - 10.1007/s00449-016-1671-0
ER  - 

@article{
author = "Ćorović, Marija and Mihailović, Mladen and Banjanac, Katarina and Carević, Milica and Milivojević, Ana and Milosavić, Nenad and Bezbradica, Dejan",
year = "2017",
abstract = "The aim of this study was to develop simple and efficient method for immobilization of Candida antarctica lipase B onto hydrophobic anion exchange resin Purolite(A (R)) MN102 and to apply immobilized catalyst for the enzymatic synthesis of two valuable esters-isoamyl acetate and l-ascorbyl oleate. At optimized conditions (1 M phosphate buffer pH = 7, 7 h at 25 A degrees C, and 18.75 mg of offered proteins g(-1) of support), immobilized lipase with hydrolytic activity of 888.4 p-nitrophenyl butyrate units g(-1) was obtained. Afterwards, preparation was applied for the solvent-free synthesis of isoamyl acetate from triacetin and isoamyl alcohol. At 75 A degrees C, 1 M of isoamyl alcohol, and 6 mg ml(-1) of enzyme 100 % yield was achieved in 6 h, while at prolonged reaction times, complete conversion was enabled even at lower temperatures, lower lipase loadings, and higher substrate concentrations. After 15 consecutive reuses (60 h), activity of catalyst dropped to 50 % of its initial value and total amount of 1.31 mol (170.55 g) of ester with 1 g of biocatalyst was produced. Even higher operational stability of lipase (25 % loss of activity in 200 h) was observed in the synthesis of l-ascorbyl oleate performed in organic solvent (t-butanol). Multiple use of one batch of immobilized biocatalyst in both cases led to a significant process cost reduction and substantial increment of corresponding productivities.",
publisher = "Springer, New York",
journal = "Bioprocess and Biosystems Engineering",
title = "Immobilization of Candida antarctica lipase B onto Purolite(A (R)) MN102 and its application in solvent-free and organic media esterification",
pages = "34-23",
number = "1",
volume = "40",
doi = "10.1007/s00449-016-1671-0"
}

Ćorović, M., Mihailović, M., Banjanac, K., Carević, M., Milivojević, A., Milosavić, N.,& Bezbradica, D.. (2017). Immobilization of Candida antarctica lipase B onto Purolite(A (R)) MN102 and its application in solvent-free and organic media esterification. in Bioprocess and Biosystems Engineering
Springer, New York., 40(1), 23-34.
https://doi.org/10.1007/s00449-016-1671-0

Ćorović M, Mihailović M, Banjanac K, Carević M, Milivojević A, Milosavić N, Bezbradica D. Immobilization of Candida antarctica lipase B onto Purolite(A (R)) MN102 and its application in solvent-free and organic media esterification. in Bioprocess and Biosystems Engineering. 2017;40(1):23-34.
doi:10.1007/s00449-016-1671-0 .

Ćorović, Marija, Mihailović, Mladen, Banjanac, Katarina, Carević, Milica, Milivojević, Ana, Milosavić, Nenad, Bezbradica, Dejan, "Immobilization of Candida antarctica lipase B onto Purolite(A (R)) MN102 and its application in solvent-free and organic media esterification" in Bioprocess and Biosystems Engineering, 40, no. 1 (2017):23-34,
https://doi.org/10.1007/s00449-016-1671-0 . .

TY  - JOUR
AU  - Trbojević-Ivić, Jovana
AU  - Milosavić, Nenad
AU  - Dimitrijević, Aleksandra
AU  - Gavrović-Jankulović, Marija
AU  - Bezbradica, Dejan
AU  - Kolarski, Dušan
AU  - Veličković, Dušan
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3659
AB  - A commercial preparation of Candida rugosa lipases (CRL) was tested for the production of capsinoids by esterification of vanillyl alcohol (VA) with free fatty acids (FA) and coconut oil (CO) as acyl donors. Screening of FA chain length indicated that C8-C12 FA (the most common FA found in CO triglycerides) are the best acyl-donors, yielding 80-85% of their specific capsinoids. Hence, when CO, which is rich in these FA, was used as the substrate, a mixture of capsinoids (vanillyl caprylate, vanillyl decanoate and vanillyl laurate) was obtained. The findings presented here suggest that our experimental method can be applied for the enrichment of CO with capsinoids, thus giving it additional health promoting properties.
PB  - Elsevier Sci Ltd, Oxford
T2  - Food Chemistry
T1  - Synthesis of medium-chain length capsinoids from coconut oil catalyzed by Candida rugosa lipases
EP  - 508
SP  - 505
VL  - 218
DO  - 10.1016/j.foodchem.2016.09.049
ER  - 

@article{
author = "Trbojević-Ivić, Jovana and Milosavić, Nenad and Dimitrijević, Aleksandra and Gavrović-Jankulović, Marija and Bezbradica, Dejan and Kolarski, Dušan and Veličković, Dušan",
year = "2017",
abstract = "A commercial preparation of Candida rugosa lipases (CRL) was tested for the production of capsinoids by esterification of vanillyl alcohol (VA) with free fatty acids (FA) and coconut oil (CO) as acyl donors. Screening of FA chain length indicated that C8-C12 FA (the most common FA found in CO triglycerides) are the best acyl-donors, yielding 80-85% of their specific capsinoids. Hence, when CO, which is rich in these FA, was used as the substrate, a mixture of capsinoids (vanillyl caprylate, vanillyl decanoate and vanillyl laurate) was obtained. The findings presented here suggest that our experimental method can be applied for the enrichment of CO with capsinoids, thus giving it additional health promoting properties.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Food Chemistry",
title = "Synthesis of medium-chain length capsinoids from coconut oil catalyzed by Candida rugosa lipases",
pages = "508-505",
volume = "218",
doi = "10.1016/j.foodchem.2016.09.049"
}

Trbojević-Ivić, J., Milosavić, N., Dimitrijević, A., Gavrović-Jankulović, M., Bezbradica, D., Kolarski, D.,& Veličković, D.. (2017). Synthesis of medium-chain length capsinoids from coconut oil catalyzed by Candida rugosa lipases. in Food Chemistry
Elsevier Sci Ltd, Oxford., 218, 505-508.
https://doi.org/10.1016/j.foodchem.2016.09.049

Trbojević-Ivić J, Milosavić N, Dimitrijević A, Gavrović-Jankulović M, Bezbradica D, Kolarski D, Veličković D. Synthesis of medium-chain length capsinoids from coconut oil catalyzed by Candida rugosa lipases. in Food Chemistry. 2017;218:505-508.
doi:10.1016/j.foodchem.2016.09.049 .

Trbojević-Ivić, Jovana, Milosavić, Nenad, Dimitrijević, Aleksandra, Gavrović-Jankulović, Marija, Bezbradica, Dejan, Kolarski, Dušan, Veličković, Dušan, "Synthesis of medium-chain length capsinoids from coconut oil catalyzed by Candida rugosa lipases" in Food Chemistry, 218 (2017):505-508,
https://doi.org/10.1016/j.foodchem.2016.09.049 . .

TY  - JOUR
AU  - Mihailović, Mladen
AU  - Trbojević-Ivić, Jovana
AU  - Banjanac, Katarina
AU  - Milosavić, Nenad
AU  - Veličković, Dušan
AU  - Simović, Milica
AU  - Bezbradica, Dejan
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3422
AB  - In this study, two commercial supports (Eupergit (R) C and Purolite (R) A109) were chemically modified in order to introduce thiosulfonate groups, which could subsequently exclusively react with the cysteine residues on the surface of enzymes. Thereafter, the maltase from Saccharomyces cerevisiae was immobilized onto the obtained thiosulfonate-activated supports, resulting in high expressed enzymatic activities (around 50 %), while on the other hand, immobilization on unmodified supports yielded expressed activities less than 5 %. Moreover, protein loadings up to 12.3 mg g(-1) and immobilized activities up to 3580 IU g(-1) were achieved by employment of these thiosulfonate supports. Desorption experiments, performed on samples taken during immobilization, proved that immobilization on the thiosulfonate supports was the first step of fast adsorption onto the supports and the formation of covalent bonds between the thiosulfonate groups and the thiol groups of cysteine represented a second slower step. More importantly, although enzyme coupling occurred via covalent bond formation, the performed immobilization proved to be reversible, since it was shown that 95 % of the immobilized activity could be detached from the support after treatment with a thiol reagent (beta-mercaptoethanol). Thus, the support could be reused after enzyme inactivation.
PB  - Srpsko hemijsko društvo, Beograd
T2  - Journal of the Serbian Chemical Society
T1  - Immobilization of maltase from Saccharomyces cerevisiae on thiosulfonate supports
EP  - 1382
IS  - 12
SP  - 1371
VL  - 81
DO  - 10.2298/JSC160730099M
ER  - 

@article{
author = "Mihailović, Mladen and Trbojević-Ivić, Jovana and Banjanac, Katarina and Milosavić, Nenad and Veličković, Dušan and Simović, Milica and Bezbradica, Dejan",
year = "2016",
abstract = "In this study, two commercial supports (Eupergit (R) C and Purolite (R) A109) were chemically modified in order to introduce thiosulfonate groups, which could subsequently exclusively react with the cysteine residues on the surface of enzymes. Thereafter, the maltase from Saccharomyces cerevisiae was immobilized onto the obtained thiosulfonate-activated supports, resulting in high expressed enzymatic activities (around 50 %), while on the other hand, immobilization on unmodified supports yielded expressed activities less than 5 %. Moreover, protein loadings up to 12.3 mg g(-1) and immobilized activities up to 3580 IU g(-1) were achieved by employment of these thiosulfonate supports. Desorption experiments, performed on samples taken during immobilization, proved that immobilization on the thiosulfonate supports was the first step of fast adsorption onto the supports and the formation of covalent bonds between the thiosulfonate groups and the thiol groups of cysteine represented a second slower step. More importantly, although enzyme coupling occurred via covalent bond formation, the performed immobilization proved to be reversible, since it was shown that 95 % of the immobilized activity could be detached from the support after treatment with a thiol reagent (beta-mercaptoethanol). Thus, the support could be reused after enzyme inactivation.",
publisher = "Srpsko hemijsko društvo, Beograd",
journal = "Journal of the Serbian Chemical Society",
title = "Immobilization of maltase from Saccharomyces cerevisiae on thiosulfonate supports",
pages = "1382-1371",
number = "12",
volume = "81",
doi = "10.2298/JSC160730099M"
}

Mihailović, M., Trbojević-Ivić, J., Banjanac, K., Milosavić, N., Veličković, D., Simović, M.,& Bezbradica, D.. (2016). Immobilization of maltase from Saccharomyces cerevisiae on thiosulfonate supports. in Journal of the Serbian Chemical Society
Srpsko hemijsko društvo, Beograd., 81(12), 1371-1382.
https://doi.org/10.2298/JSC160730099M

Mihailović M, Trbojević-Ivić J, Banjanac K, Milosavić N, Veličković D, Simović M, Bezbradica D. Immobilization of maltase from Saccharomyces cerevisiae on thiosulfonate supports. in Journal of the Serbian Chemical Society. 2016;81(12):1371-1382.
doi:10.2298/JSC160730099M .

Mihailović, Mladen, Trbojević-Ivić, Jovana, Banjanac, Katarina, Milosavić, Nenad, Veličković, Dušan, Simović, Milica, Bezbradica, Dejan, "Immobilization of maltase from Saccharomyces cerevisiae on thiosulfonate supports" in Journal of the Serbian Chemical Society, 81, no. 12 (2016):1371-1382,
https://doi.org/10.2298/JSC160730099M . .

TY  - JOUR
AU  - Trbojević-Ivić, Jovana
AU  - Dimitrijević, Aleksandra
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
AU  - Drakulić, Branko
AU  - Gavrović-Jankulović, Marija
AU  - Pavlović, Marija
AU  - Rogniaux, Helene
AU  - Veličković, Dušan
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3442
AB  - Hydroxyapatite (HAP), a calcium-phosphate bioactive ceramic, is actively employed in medical and separation sciences. Although different classes of biomacromolecules interact with this material, interactions with proteins are the most important, since they directly affect the biocompatibility of the carrier and it's industrial application. In the presented work, we thoroughly investigate and elucidate the interaction mechanism between Candida rugosa lipase (CRL) upon it's immobilization on HAP, since this immobilized enzyme showed advanced catalytic properties in previous studies. Applying elution and protein modification strategies we concluded that Ca-chelation of HAP's C-site and CRL's -COOH groups is the most probable interacting mechanism. A proteomics approach revealed that this chelation is conserved throughout all CRL isoforms, while results of molecular modelling led us to propose the involvement of a specific region of the protein surface and side chains in interactions with HAP.
PB  - Royal Soc Chemistry, Cambridge
T2  - RSC Advances
T1  - Assessment of the interacting mechanism between Candida rugosa lipases and hydroxyapatite and identification of the hydroxyapatite-binding sequence through proteomics and molecular modelling
EP  - 34824
IS  - 41
SP  - 34818
VL  - 6
DO  - 10.1039/c6ra07521e
ER  - 

@article{
author = "Trbojević-Ivić, Jovana and Dimitrijević, Aleksandra and Milosavić, Nenad and Bezbradica, Dejan and Drakulić, Branko and Gavrović-Jankulović, Marija and Pavlović, Marija and Rogniaux, Helene and Veličković, Dušan",
year = "2016",
abstract = "Hydroxyapatite (HAP), a calcium-phosphate bioactive ceramic, is actively employed in medical and separation sciences. Although different classes of biomacromolecules interact with this material, interactions with proteins are the most important, since they directly affect the biocompatibility of the carrier and it's industrial application. In the presented work, we thoroughly investigate and elucidate the interaction mechanism between Candida rugosa lipase (CRL) upon it's immobilization on HAP, since this immobilized enzyme showed advanced catalytic properties in previous studies. Applying elution and protein modification strategies we concluded that Ca-chelation of HAP's C-site and CRL's -COOH groups is the most probable interacting mechanism. A proteomics approach revealed that this chelation is conserved throughout all CRL isoforms, while results of molecular modelling led us to propose the involvement of a specific region of the protein surface and side chains in interactions with HAP.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "RSC Advances",
title = "Assessment of the interacting mechanism between Candida rugosa lipases and hydroxyapatite and identification of the hydroxyapatite-binding sequence through proteomics and molecular modelling",
pages = "34824-34818",
number = "41",
volume = "6",
doi = "10.1039/c6ra07521e"
}

Trbojević-Ivić, J., Dimitrijević, A., Milosavić, N., Bezbradica, D., Drakulić, B., Gavrović-Jankulović, M., Pavlović, M., Rogniaux, H.,& Veličković, D.. (2016). Assessment of the interacting mechanism between Candida rugosa lipases and hydroxyapatite and identification of the hydroxyapatite-binding sequence through proteomics and molecular modelling. in RSC Advances
Royal Soc Chemistry, Cambridge., 6(41), 34818-34824.
https://doi.org/10.1039/c6ra07521e

Trbojević-Ivić J, Dimitrijević A, Milosavić N, Bezbradica D, Drakulić B, Gavrović-Jankulović M, Pavlović M, Rogniaux H, Veličković D. Assessment of the interacting mechanism between Candida rugosa lipases and hydroxyapatite and identification of the hydroxyapatite-binding sequence through proteomics and molecular modelling. in RSC Advances. 2016;6(41):34818-34824.
doi:10.1039/c6ra07521e .

Trbojević-Ivić, Jovana, Dimitrijević, Aleksandra, Milosavić, Nenad, Bezbradica, Dejan, Drakulić, Branko, Gavrović-Jankulović, Marija, Pavlović, Marija, Rogniaux, Helene, Veličković, Dušan, "Assessment of the interacting mechanism between Candida rugosa lipases and hydroxyapatite and identification of the hydroxyapatite-binding sequence through proteomics and molecular modelling" in RSC Advances, 6, no. 41 (2016):34818-34824,
https://doi.org/10.1039/c6ra07521e . .

TY  - JOUR
AU  - Trbojević-Ivić, Jovana
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Bezbradica, Dejan
AU  - Dragacević, Vladimir
AU  - Gavrović-Jankulović, Marija
AU  - Milosavić, Nenad
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3225
AB  - BACKGROUNDBiocatalysts are a promising alternative for the production of natural flavor compounds. Candida rugosa lipase (CRL) is a particularly important biocatalyst owing to its remarkable efficiency in both hydrolysis and synthesis. However, additional stabilization is necessary for successful industrial implementation. This study presents an easy and time-saving method for immobilizing this valuable enzyme on hydroxyapatite (HAP), a biomaterial with high protein-binding capacity. RESULTSTargeted immobilized CRL was obtained in high yield of 98%. Significant lipase stabilization was observed upon immobilization: at 60 degrees C, immobilized lipase (HAP-CRL) retained almost unchanged activity after 3h, while free CRL lost 50% of its initial activity after only 30min. The same trend was observed with tested organic solvents. Methanol and hexane had the most pronounced effect: after 3h, only HAP-CRL was stable and active, while CRL was completely inactivated. The practical value of the prepared catalyst was tested in the synthesis of the aroma ester methyl acetate in hexane. Reaction yields were 2.6 and 52.5% for CRL and HAP-CRL respectively. CONCLUSIONThis research has successfully combined an industrially prominent biocatalyst, CRL, and a biocompatible, environmentally suitable carrier, HAP, into an immobilized preparation with improved catalytic properties. The obtained CRL preparation has excellent potential for the food and flavor industries, major consumers in the global enzyme market.
PB  - Wiley-Blackwell, Hoboken
T2  - Journal of the Science of Food and Agriculture
T1  - Design of biocompatible immobilized Candida rugosa lipase with potential application in food industry
EP  - 4287
IS  - 12
SP  - 4281
VL  - 96
DO  - 10.1002/jsfa.7641
ER  - 

@article{
author = "Trbojević-Ivić, Jovana and Veličković, Dušan and Dimitrijević, Aleksandra and Bezbradica, Dejan and Dragacević, Vladimir and Gavrović-Jankulović, Marija and Milosavić, Nenad",
year = "2016",
abstract = "BACKGROUNDBiocatalysts are a promising alternative for the production of natural flavor compounds. Candida rugosa lipase (CRL) is a particularly important biocatalyst owing to its remarkable efficiency in both hydrolysis and synthesis. However, additional stabilization is necessary for successful industrial implementation. This study presents an easy and time-saving method for immobilizing this valuable enzyme on hydroxyapatite (HAP), a biomaterial with high protein-binding capacity. RESULTSTargeted immobilized CRL was obtained in high yield of 98%. Significant lipase stabilization was observed upon immobilization: at 60 degrees C, immobilized lipase (HAP-CRL) retained almost unchanged activity after 3h, while free CRL lost 50% of its initial activity after only 30min. The same trend was observed with tested organic solvents. Methanol and hexane had the most pronounced effect: after 3h, only HAP-CRL was stable and active, while CRL was completely inactivated. The practical value of the prepared catalyst was tested in the synthesis of the aroma ester methyl acetate in hexane. Reaction yields were 2.6 and 52.5% for CRL and HAP-CRL respectively. CONCLUSIONThis research has successfully combined an industrially prominent biocatalyst, CRL, and a biocompatible, environmentally suitable carrier, HAP, into an immobilized preparation with improved catalytic properties. The obtained CRL preparation has excellent potential for the food and flavor industries, major consumers in the global enzyme market.",
publisher = "Wiley-Blackwell, Hoboken",
journal = "Journal of the Science of Food and Agriculture",
title = "Design of biocompatible immobilized Candida rugosa lipase with potential application in food industry",
pages = "4287-4281",
number = "12",
volume = "96",
doi = "10.1002/jsfa.7641"
}

Trbojević-Ivić, J., Veličković, D., Dimitrijević, A., Bezbradica, D., Dragacević, V., Gavrović-Jankulović, M.,& Milosavić, N.. (2016). Design of biocompatible immobilized Candida rugosa lipase with potential application in food industry. in Journal of the Science of Food and Agriculture
Wiley-Blackwell, Hoboken., 96(12), 4281-4287.
https://doi.org/10.1002/jsfa.7641

Trbojević-Ivić J, Veličković D, Dimitrijević A, Bezbradica D, Dragacević V, Gavrović-Jankulović M, Milosavić N. Design of biocompatible immobilized Candida rugosa lipase with potential application in food industry. in Journal of the Science of Food and Agriculture. 2016;96(12):4281-4287.
doi:10.1002/jsfa.7641 .

Trbojević-Ivić, Jovana, Veličković, Dušan, Dimitrijević, Aleksandra, Bezbradica, Dejan, Dragacević, Vladimir, Gavrović-Jankulović, Marija, Milosavić, Nenad, "Design of biocompatible immobilized Candida rugosa lipase with potential application in food industry" in Journal of the Science of Food and Agriculture, 96, no. 12 (2016):4281-4287,
https://doi.org/10.1002/jsfa.7641 . .

TY  - JOUR
AU  - Stojanović, Marija
AU  - Simović, Milica
AU  - Mihailović, Mladen
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4720
AB  - Fatty acid (FA) ascorbyl esters are recently emerging food, cosmetic, and pharmaceutical additives, which can be prepared in an eco-friendly way by using lipases as catalysts. Because they are amphiphilic molecules, which possess high free radical scavenging capacity, they can be applied as liposoluble antioxidants as well as emulsifiers and biosurfactants. In this study, the influence of a wide range of acyl donors on ester yield in lipase-catalyzed synthesis and ester antioxidant activity was examined. Among saturated acyl donors, higher yields and antioxidant activities of esters were achieved when short-chain FAs were used. Oleic acid gave the highest yield overall and its ester exhibited a high antioxidant activity. Optimization of experimental factors showed that the highest conversion (60.5%) in acetone was achieved with 5 g L-1 of lipase, 50 mM of vitamin C, 10-fold molar excess of oleic acid, and 0.7 mL L-1 of initial water. Obtained results showed that even short- and medium-chain ascorbyl esters could be synthesized with high yields and retained (or even exceeded) free radical scavenging capacity of l-ascorbic acid, indicating prospects of broadening their application in emulsions and liposomes.
PB  - Wiley, Hoboken
T2  - Biotechnology and Applied Biochemistry
T1  - Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity
EP  - 466
IS  - 4
SP  - 458
VL  - 62
DO  - 10.1002/bab.1296
ER  - 

@article{
author = "Stojanović, Marija and Simović, Milica and Mihailović, Mladen and Veličković, Dušan and Dimitrijević, Aleksandra and Milosavić, Nenad and Bezbradica, Dejan",
year = "2015",
abstract = "Fatty acid (FA) ascorbyl esters are recently emerging food, cosmetic, and pharmaceutical additives, which can be prepared in an eco-friendly way by using lipases as catalysts. Because they are amphiphilic molecules, which possess high free radical scavenging capacity, they can be applied as liposoluble antioxidants as well as emulsifiers and biosurfactants. In this study, the influence of a wide range of acyl donors on ester yield in lipase-catalyzed synthesis and ester antioxidant activity was examined. Among saturated acyl donors, higher yields and antioxidant activities of esters were achieved when short-chain FAs were used. Oleic acid gave the highest yield overall and its ester exhibited a high antioxidant activity. Optimization of experimental factors showed that the highest conversion (60.5%) in acetone was achieved with 5 g L-1 of lipase, 50 mM of vitamin C, 10-fold molar excess of oleic acid, and 0.7 mL L-1 of initial water. Obtained results showed that even short- and medium-chain ascorbyl esters could be synthesized with high yields and retained (or even exceeded) free radical scavenging capacity of l-ascorbic acid, indicating prospects of broadening their application in emulsions and liposomes.",
publisher = "Wiley, Hoboken",
journal = "Biotechnology and Applied Biochemistry",
title = "Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity",
pages = "466-458",
number = "4",
volume = "62",
doi = "10.1002/bab.1296"
}

Stojanović, M., Simović, M., Mihailović, M., Veličković, D., Dimitrijević, A., Milosavić, N.,& Bezbradica, D.. (2015). Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity. in Biotechnology and Applied Biochemistry
Wiley, Hoboken., 62(4), 458-466.
https://doi.org/10.1002/bab.1296

Stojanović M, Simović M, Mihailović M, Veličković D, Dimitrijević A, Milosavić N, Bezbradica D. Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity. in Biotechnology and Applied Biochemistry. 2015;62(4):458-466.
doi:10.1002/bab.1296 .

Stojanović, Marija, Simović, Milica, Mihailović, Mladen, Veličković, Dušan, Dimitrijević, Aleksandra, Milosavić, Nenad, Bezbradica, Dejan, "Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity" in Biotechnology and Applied Biochemistry, 62, no. 4 (2015):458-466,
https://doi.org/10.1002/bab.1296 . .

TY  - JOUR
AU  - Stojanović, Marija
AU  - Simović, Milica
AU  - Mihailović, Mladen
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3146
AB  - Fatty acid (FA) ascorbyl esters are recently emerging food, cosmetic, and pharmaceutical additives, which can be prepared in an eco-friendly way by using lipases as catalysts. Because they are amphiphilic molecules, which possess high free radical scavenging capacity, they can be applied as liposoluble antioxidants as well as emulsifiers and biosurfactants. In this study, the influence of a wide range of acyl donors on ester yield in lipase-catalyzed synthesis and ester antioxidant activity was examined. Among saturated acyl donors, higher yields and antioxidant activities of esters were achieved when short-chain FAs were used. Oleic acid gave the highest yield overall and its ester exhibited a high antioxidant activity. Optimization of experimental factors showed that the highest conversion (60.5%) in acetone was achieved with 5 g L-1 of lipase, 50 mM of vitamin C, 10-fold molar excess of oleic acid, and 0.7 mL L-1 of initial water. Obtained results showed that even short- and medium-chain ascorbyl esters could be synthesized with high yields and retained (or even exceeded) free radical scavenging capacity of l-ascorbic acid, indicating prospects of broadening their application in emulsions and liposomes.
PB  - Wiley, Hoboken
T2  - Biotechnology and Applied Biochemistry
T1  - Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity
EP  - 466
IS  - 4
SP  - 458
VL  - 62
DO  - 10.1002/bab.1296
ER  - 

@article{
author = "Stojanović, Marija and Simović, Milica and Mihailović, Mladen and Veličković, Dušan and Dimitrijević, Aleksandra and Milosavić, Nenad and Bezbradica, Dejan",
year = "2015",
abstract = "Fatty acid (FA) ascorbyl esters are recently emerging food, cosmetic, and pharmaceutical additives, which can be prepared in an eco-friendly way by using lipases as catalysts. Because they are amphiphilic molecules, which possess high free radical scavenging capacity, they can be applied as liposoluble antioxidants as well as emulsifiers and biosurfactants. In this study, the influence of a wide range of acyl donors on ester yield in lipase-catalyzed synthesis and ester antioxidant activity was examined. Among saturated acyl donors, higher yields and antioxidant activities of esters were achieved when short-chain FAs were used. Oleic acid gave the highest yield overall and its ester exhibited a high antioxidant activity. Optimization of experimental factors showed that the highest conversion (60.5%) in acetone was achieved with 5 g L-1 of lipase, 50 mM of vitamin C, 10-fold molar excess of oleic acid, and 0.7 mL L-1 of initial water. Obtained results showed that even short- and medium-chain ascorbyl esters could be synthesized with high yields and retained (or even exceeded) free radical scavenging capacity of l-ascorbic acid, indicating prospects of broadening their application in emulsions and liposomes.",
publisher = "Wiley, Hoboken",
journal = "Biotechnology and Applied Biochemistry",
title = "Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity",
pages = "466-458",
number = "4",
volume = "62",
doi = "10.1002/bab.1296"
}

Stojanović, M., Simović, M., Mihailović, M., Veličković, D., Dimitrijević, A., Milosavić, N.,& Bezbradica, D.. (2015). Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity. in Biotechnology and Applied Biochemistry
Wiley, Hoboken., 62(4), 458-466.
https://doi.org/10.1002/bab.1296

Stojanović M, Simović M, Mihailović M, Veličković D, Dimitrijević A, Milosavić N, Bezbradica D. Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity. in Biotechnology and Applied Biochemistry. 2015;62(4):458-466.
doi:10.1002/bab.1296 .

Stojanović, Marija, Simović, Milica, Mihailović, Mladen, Veličković, Dušan, Dimitrijević, Aleksandra, Milosavić, Nenad, Bezbradica, Dejan, "Influence of fatty acid on lipase-catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity" in Biotechnology and Applied Biochemistry, 62, no. 4 (2015):458-466,
https://doi.org/10.1002/bab.1296 . .

TY  - JOUR
AU  - Simović, Milica
AU  - Veličković, Dušan
AU  - Stojanović, Marija
AU  - Milosavić, Nenad
AU  - Rogniaux, Helene
AU  - Ropartz, David
AU  - Bezbradica, Dejan
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3018
AB  - In this study, enzymatic synthesis of galactoside of salicin, compound with potential physiological activity due to structural resemblance with galectin inhibitors, and analgesic and antipyretic properties of salicin, was performed using beta-galactosidase from Aspergillus oryzae. It was determined, using HPLC and ion mobility mass spectrometry, that enzymatic synthesis was highly selective since only one isomer was formed via primary hydroxyl group on glucose moiety of salicin. The optimization of key experimental factors using response surface methodology enabled galactosyl salicin concentration up to 30.8 mM obtained at lactose concentration 40 mM, salicin concentration 110 mM, enzyme amount 360 IU and reaction time 12 h.
PB  - Elsevier Sci Ltd, Oxford
T2  - Process Biochemistry
T1  - Insight in the regioselective enzymatic transgalactosylation of salicin catalyzed by beta-galactosidase from Aspergillus oryzae
EP  - 788
IS  - 5
SP  - 782
VL  - 50
DO  - 10.1016/j.procbio.2015.01.028
ER  - 

@article{
author = "Simović, Milica and Veličković, Dušan and Stojanović, Marija and Milosavić, Nenad and Rogniaux, Helene and Ropartz, David and Bezbradica, Dejan",
year = "2015",
abstract = "In this study, enzymatic synthesis of galactoside of salicin, compound with potential physiological activity due to structural resemblance with galectin inhibitors, and analgesic and antipyretic properties of salicin, was performed using beta-galactosidase from Aspergillus oryzae. It was determined, using HPLC and ion mobility mass spectrometry, that enzymatic synthesis was highly selective since only one isomer was formed via primary hydroxyl group on glucose moiety of salicin. The optimization of key experimental factors using response surface methodology enabled galactosyl salicin concentration up to 30.8 mM obtained at lactose concentration 40 mM, salicin concentration 110 mM, enzyme amount 360 IU and reaction time 12 h.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Process Biochemistry",
title = "Insight in the regioselective enzymatic transgalactosylation of salicin catalyzed by beta-galactosidase from Aspergillus oryzae",
pages = "788-782",
number = "5",
volume = "50",
doi = "10.1016/j.procbio.2015.01.028"
}

Simović, M., Veličković, D., Stojanović, M., Milosavić, N., Rogniaux, H., Ropartz, D.,& Bezbradica, D.. (2015). Insight in the regioselective enzymatic transgalactosylation of salicin catalyzed by beta-galactosidase from Aspergillus oryzae. in Process Biochemistry
Elsevier Sci Ltd, Oxford., 50(5), 782-788.
https://doi.org/10.1016/j.procbio.2015.01.028

Simović M, Veličković D, Stojanović M, Milosavić N, Rogniaux H, Ropartz D, Bezbradica D. Insight in the regioselective enzymatic transgalactosylation of salicin catalyzed by beta-galactosidase from Aspergillus oryzae. in Process Biochemistry. 2015;50(5):782-788.
doi:10.1016/j.procbio.2015.01.028 .

Simović, Milica, Veličković, Dušan, Stojanović, Marija, Milosavić, Nenad, Rogniaux, Helene, Ropartz, David, Bezbradica, Dejan, "Insight in the regioselective enzymatic transgalactosylation of salicin catalyzed by beta-galactosidase from Aspergillus oryzae" in Process Biochemistry, 50, no. 5 (2015):782-788,
https://doi.org/10.1016/j.procbio.2015.01.028 . .

TY  - JOUR
AU  - Milivojević, Ana
AU  - Stojanović, Marija
AU  - Carević, Milica
AU  - Mihailović, Mladen
AU  - Veličković, Dušan
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2744
AB  - Lipase-catalyzed acylation of phloridzin with a wide range of fatty acids and antioxidant activities of synthesized esters were investigated in this study. Polar solvents were suitable reaction media for esterification, and the highest yield was achieved in acetonitrile. By using statistically designed optimization of key experimental factors for the synthesis of phloridzil oleate as the model reaction, great improvements in achieved conversion and yield per enzyme mass were enabled. The most significant progress has been made in the cost-effectiveness of the reaction, since the specific yield of 5.45 mmol g(-1) was obtained at 58 degrees C, with 0.09 M phloridzin, 1.17 M oleic acid, and only 0.5% (w/v) biocatalyst. All examined fatty acids were suitable acyl donors, since the chain length and unsaturation degree had slight effects on esterification and all products yielded over 70%. Phloridzil caprate, myristate, and oleate exhibited the highest antioxidant activities among the obtained esters.
PB  - Amer Chemical Soc, Washington
T2  - Industrial & Engineering Chemistry Research
T1  - Lipase-Catalyzed Esterification of Phloridzin: Acyl Donor Effect on Enzymatic Affinity and Antioxidant Properties of Esters
EP  - 16651
IS  - 43
SP  - 16644
VL  - 53
DO  - 10.1021/ie5027259
ER  - 

@article{
author = "Milivojević, Ana and Stojanović, Marija and Carević, Milica and Mihailović, Mladen and Veličković, Dušan and Milosavić, Nenad and Bezbradica, Dejan",
year = "2014",
abstract = "Lipase-catalyzed acylation of phloridzin with a wide range of fatty acids and antioxidant activities of synthesized esters were investigated in this study. Polar solvents were suitable reaction media for esterification, and the highest yield was achieved in acetonitrile. By using statistically designed optimization of key experimental factors for the synthesis of phloridzil oleate as the model reaction, great improvements in achieved conversion and yield per enzyme mass were enabled. The most significant progress has been made in the cost-effectiveness of the reaction, since the specific yield of 5.45 mmol g(-1) was obtained at 58 degrees C, with 0.09 M phloridzin, 1.17 M oleic acid, and only 0.5% (w/v) biocatalyst. All examined fatty acids were suitable acyl donors, since the chain length and unsaturation degree had slight effects on esterification and all products yielded over 70%. Phloridzil caprate, myristate, and oleate exhibited the highest antioxidant activities among the obtained esters.",
publisher = "Amer Chemical Soc, Washington",
journal = "Industrial & Engineering Chemistry Research",
title = "Lipase-Catalyzed Esterification of Phloridzin: Acyl Donor Effect on Enzymatic Affinity and Antioxidant Properties of Esters",
pages = "16651-16644",
number = "43",
volume = "53",
doi = "10.1021/ie5027259"
}

Milivojević, A., Stojanović, M., Carević, M., Mihailović, M., Veličković, D., Milosavić, N.,& Bezbradica, D.. (2014). Lipase-Catalyzed Esterification of Phloridzin: Acyl Donor Effect on Enzymatic Affinity and Antioxidant Properties of Esters. in Industrial & Engineering Chemistry Research
Amer Chemical Soc, Washington., 53(43), 16644-16651.
https://doi.org/10.1021/ie5027259

Milivojević A, Stojanović M, Carević M, Mihailović M, Veličković D, Milosavić N, Bezbradica D. Lipase-Catalyzed Esterification of Phloridzin: Acyl Donor Effect on Enzymatic Affinity and Antioxidant Properties of Esters. in Industrial & Engineering Chemistry Research. 2014;53(43):16644-16651.
doi:10.1021/ie5027259 .

Milivojević, Ana, Stojanović, Marija, Carević, Milica, Mihailović, Mladen, Veličković, Dušan, Milosavić, Nenad, Bezbradica, Dejan, "Lipase-Catalyzed Esterification of Phloridzin: Acyl Donor Effect on Enzymatic Affinity and Antioxidant Properties of Esters" in Industrial & Engineering Chemistry Research, 53, no. 43 (2014):16644-16651,
https://doi.org/10.1021/ie5027259 . .

TY  - JOUR
AU  - Mihailović, Mladen
AU  - Stojanović, Marija
AU  - Banjanac, Katarina
AU  - Carević, Milica
AU  - Prlainović, Nevena
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2853
AB  - In this study, Purolite (R) A109, polystyrenic macroporous resin, was used as immobilization support due to its good mechanical properties and high particle diameter (400 mu m), which enables efficient application in enzyme reactors due to lower pressure drops. The surface of support had been modified with epichlorhydrine and was tested in lipase immobilization. Optimized procedure for support modification proved to be more efficient than conventional procedure for hydroxy groups (at 22 degrees C for 18 h), since duration of procedure was shortened to 40 min by performing modification at 52 degrees C resulting with almost doubled concentration of epoxy groups (563 mu mol g(-1)). Lipase immobilized on epoxy-modified support showed significantly improved thermal stability comparing to both, free form and commercial immobilized preparation (Novozym (R) 435). The highest activity (47.5 IU g(-1)) and thermal stability (2.5 times higher half-life than at low ionic strength) were obtained with lipase immobilized in high ionic strength. Thermal stability of immobilized lipase was further improved by blocking unreacted epoxy groups on supports surface with amino acids. The most efficient was treatment with phenylalanine, since in such a way blocked immobilized enzyme retained 65% of initial activity after 8 h incubation at 65 degrees C, while non-blocked derivative retained 12%.
PB  - Elsevier Sci Ltd, Oxford
T2  - Process Biochemistry
T1  - Immobilization of lipase on epoxy-activated Purolite((R)) A109 and its post-immobilization stabilization
EP  - 646
IS  - 4
SP  - 637
VL  - 49
DO  - 10.1016/j.procbio.2014.01.013
ER  - 

@article{
author = "Mihailović, Mladen and Stojanović, Marija and Banjanac, Katarina and Carević, Milica and Prlainović, Nevena and Milosavić, Nenad and Bezbradica, Dejan",
year = "2014",
abstract = "In this study, Purolite (R) A109, polystyrenic macroporous resin, was used as immobilization support due to its good mechanical properties and high particle diameter (400 mu m), which enables efficient application in enzyme reactors due to lower pressure drops. The surface of support had been modified with epichlorhydrine and was tested in lipase immobilization. Optimized procedure for support modification proved to be more efficient than conventional procedure for hydroxy groups (at 22 degrees C for 18 h), since duration of procedure was shortened to 40 min by performing modification at 52 degrees C resulting with almost doubled concentration of epoxy groups (563 mu mol g(-1)). Lipase immobilized on epoxy-modified support showed significantly improved thermal stability comparing to both, free form and commercial immobilized preparation (Novozym (R) 435). The highest activity (47.5 IU g(-1)) and thermal stability (2.5 times higher half-life than at low ionic strength) were obtained with lipase immobilized in high ionic strength. Thermal stability of immobilized lipase was further improved by blocking unreacted epoxy groups on supports surface with amino acids. The most efficient was treatment with phenylalanine, since in such a way blocked immobilized enzyme retained 65% of initial activity after 8 h incubation at 65 degrees C, while non-blocked derivative retained 12%.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Process Biochemistry",
title = "Immobilization of lipase on epoxy-activated Purolite((R)) A109 and its post-immobilization stabilization",
pages = "646-637",
number = "4",
volume = "49",
doi = "10.1016/j.procbio.2014.01.013"
}

Mihailović, M., Stojanović, M., Banjanac, K., Carević, M., Prlainović, N., Milosavić, N.,& Bezbradica, D.. (2014). Immobilization of lipase on epoxy-activated Purolite((R)) A109 and its post-immobilization stabilization. in Process Biochemistry
Elsevier Sci Ltd, Oxford., 49(4), 637-646.
https://doi.org/10.1016/j.procbio.2014.01.013

Mihailović M, Stojanović M, Banjanac K, Carević M, Prlainović N, Milosavić N, Bezbradica D. Immobilization of lipase on epoxy-activated Purolite((R)) A109 and its post-immobilization stabilization. in Process Biochemistry. 2014;49(4):637-646.
doi:10.1016/j.procbio.2014.01.013 .

Mihailović, Mladen, Stojanović, Marija, Banjanac, Katarina, Carević, Milica, Prlainović, Nevena, Milosavić, Nenad, Bezbradica, Dejan, "Immobilization of lipase on epoxy-activated Purolite((R)) A109 and its post-immobilization stabilization" in Process Biochemistry, 49, no. 4 (2014):637-646,
https://doi.org/10.1016/j.procbio.2014.01.013 . .

TY  - JOUR
AU  - Pavlović, Marija
AU  - Dimitrijević, Aleksandra
AU  - Bezbradica, Dejan
AU  - Milosavić, Nenad
AU  - Gavrović-Jankulović, Marija
AU  - Šegan, Dejan M.
AU  - Veličković, Dušan
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2753
AB  - Benzyl alcohol, a potent anesthetic and bacteriostatic, can be efficiently glucosylated by alpha-glucosidase from Saccharomyces cerevisiae to produce benzyl alcohol alpha-glucoside with a 75% yield. However, while studying the transglucosylation reaction conditions, it was found out that benzyl alcohol is a non-competitive inhibitor of alpha-glucosidase's hydrolytic activity (K-i = 18 mM, toward maltose). Due to its interesting ability to be glycosylated by the enzyme and to inhibit its hydrolytic activity, we proposed a plausible mechanism for the phenolic alpha-glucosydase inhibitor's binding, since the mechanism of inhibition has not yet been elucidated.
PB  - Elsevier Sci Ltd, Oxford
T2  - Carbohydrate Research
T1  - Dual effect of benzyl alcohol on alpha-glucosidase activity: efficient substrate for high yield transglucosylation and non-competitive inhibitor of its hydrolytic activity
EP  - 18
SP  - 14
VL  - 387
DO  - 10.1016/j.carres.2013.08.028
ER  - 

@article{
author = "Pavlović, Marija and Dimitrijević, Aleksandra and Bezbradica, Dejan and Milosavić, Nenad and Gavrović-Jankulović, Marija and Šegan, Dejan M. and Veličković, Dušan",
year = "2014",
abstract = "Benzyl alcohol, a potent anesthetic and bacteriostatic, can be efficiently glucosylated by alpha-glucosidase from Saccharomyces cerevisiae to produce benzyl alcohol alpha-glucoside with a 75% yield. However, while studying the transglucosylation reaction conditions, it was found out that benzyl alcohol is a non-competitive inhibitor of alpha-glucosidase's hydrolytic activity (K-i = 18 mM, toward maltose). Due to its interesting ability to be glycosylated by the enzyme and to inhibit its hydrolytic activity, we proposed a plausible mechanism for the phenolic alpha-glucosydase inhibitor's binding, since the mechanism of inhibition has not yet been elucidated.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Carbohydrate Research",
title = "Dual effect of benzyl alcohol on alpha-glucosidase activity: efficient substrate for high yield transglucosylation and non-competitive inhibitor of its hydrolytic activity",
pages = "18-14",
volume = "387",
doi = "10.1016/j.carres.2013.08.028"
}

Pavlović, M., Dimitrijević, A., Bezbradica, D., Milosavić, N., Gavrović-Jankulović, M., Šegan, D. M.,& Veličković, D.. (2014). Dual effect of benzyl alcohol on alpha-glucosidase activity: efficient substrate for high yield transglucosylation and non-competitive inhibitor of its hydrolytic activity. in Carbohydrate Research
Elsevier Sci Ltd, Oxford., 387, 14-18.
https://doi.org/10.1016/j.carres.2013.08.028

Pavlović M, Dimitrijević A, Bezbradica D, Milosavić N, Gavrović-Jankulović M, Šegan DM, Veličković D. Dual effect of benzyl alcohol on alpha-glucosidase activity: efficient substrate for high yield transglucosylation and non-competitive inhibitor of its hydrolytic activity. in Carbohydrate Research. 2014;387:14-18.
doi:10.1016/j.carres.2013.08.028 .

Pavlović, Marija, Dimitrijević, Aleksandra, Bezbradica, Dejan, Milosavić, Nenad, Gavrović-Jankulović, Marija, Šegan, Dejan M., Veličković, Dušan, "Dual effect of benzyl alcohol on alpha-glucosidase activity: efficient substrate for high yield transglucosylation and non-competitive inhibitor of its hydrolytic activity" in Carbohydrate Research, 387 (2014):14-18,
https://doi.org/10.1016/j.carres.2013.08.028 . .

TY  - JOUR
AU  - Veličković, Dušan
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
AU  - Bihelović, Filip
AU  - Segal, Ann Marie
AU  - Šegan, Dejan M.
AU  - Trbojević-Ivić, Jovana
AU  - Dimitrijević, Aleksandra
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2788
AB  - Our investigation of the catalytic properties of Saccharomyces cerevisiae alpha-glucosidase (AGL) using hydroxybenzyl alcohol (HBA) isomers as transglucosylation substrates and their glucosides in hydrolytic reactions demonstrated interesting findings pertaining to the aglycon specificity of this important enzyme. AGL specificity increased from the para(p)- to the ortho(o)-HBA isomer in transglucosylation, whereas such AGL aglycon specificity was not seen in hydrolysis, thus indicating that the second step of the reaction (i.e., binding of the glucosyl acceptor) is rate-determining. To study the influence of substitution pattern on AGL kinetics, we compared AGL specificity, inferred from kinetic constants, for HBA isomers and other aglycon substrates. The demonstrated inhibitory effects of HBA isomers and their corresponding glucosides on AGL-catalyzed hydrolysis of p-nitrophenyl a-glucoside (PNPG) suggest that HBA glucosides act as competitive, whereas HBA isomers are noncompetitive, inhibitors. As such, we postulate that aromatic moieties cannot bind to an active site unless an enzyme-glucosyl complex has already formed, but they can interact with other regions of the enzyme molecule resulting in inhibition.
PB  - Springer, New York
T2  - Applied Microbiology and Biotechnology
T1  - The specificity of alpha-glucosidase from Saccharomyces cerevisiae differs depending on the type of reaction: hydrolysis versus transglucosylation
EP  - 6328
IS  - 14
SP  - 6317
VL  - 98
DO  - 10.1007/s00253-014-5587-9
ER  - 

@article{
author = "Veličković, Dušan and Milosavić, Nenad and Bezbradica, Dejan and Bihelović, Filip and Segal, Ann Marie and Šegan, Dejan M. and Trbojević-Ivić, Jovana and Dimitrijević, Aleksandra",
year = "2014",
abstract = "Our investigation of the catalytic properties of Saccharomyces cerevisiae alpha-glucosidase (AGL) using hydroxybenzyl alcohol (HBA) isomers as transglucosylation substrates and their glucosides in hydrolytic reactions demonstrated interesting findings pertaining to the aglycon specificity of this important enzyme. AGL specificity increased from the para(p)- to the ortho(o)-HBA isomer in transglucosylation, whereas such AGL aglycon specificity was not seen in hydrolysis, thus indicating that the second step of the reaction (i.e., binding of the glucosyl acceptor) is rate-determining. To study the influence of substitution pattern on AGL kinetics, we compared AGL specificity, inferred from kinetic constants, for HBA isomers and other aglycon substrates. The demonstrated inhibitory effects of HBA isomers and their corresponding glucosides on AGL-catalyzed hydrolysis of p-nitrophenyl a-glucoside (PNPG) suggest that HBA glucosides act as competitive, whereas HBA isomers are noncompetitive, inhibitors. As such, we postulate that aromatic moieties cannot bind to an active site unless an enzyme-glucosyl complex has already formed, but they can interact with other regions of the enzyme molecule resulting in inhibition.",
publisher = "Springer, New York",
journal = "Applied Microbiology and Biotechnology",
title = "The specificity of alpha-glucosidase from Saccharomyces cerevisiae differs depending on the type of reaction: hydrolysis versus transglucosylation",
pages = "6328-6317",
number = "14",
volume = "98",
doi = "10.1007/s00253-014-5587-9"
}

Veličković, D., Milosavić, N., Bezbradica, D., Bihelović, F., Segal, A. M., Šegan, D. M., Trbojević-Ivić, J.,& Dimitrijević, A.. (2014). The specificity of alpha-glucosidase from Saccharomyces cerevisiae differs depending on the type of reaction: hydrolysis versus transglucosylation. in Applied Microbiology and Biotechnology
Springer, New York., 98(14), 6317-6328.
https://doi.org/10.1007/s00253-014-5587-9

Veličković D, Milosavić N, Bezbradica D, Bihelović F, Segal AM, Šegan DM, Trbojević-Ivić J, Dimitrijević A. The specificity of alpha-glucosidase from Saccharomyces cerevisiae differs depending on the type of reaction: hydrolysis versus transglucosylation. in Applied Microbiology and Biotechnology. 2014;98(14):6317-6328.
doi:10.1007/s00253-014-5587-9 .

Veličković, Dušan, Milosavić, Nenad, Bezbradica, Dejan, Bihelović, Filip, Segal, Ann Marie, Šegan, Dejan M., Trbojević-Ivić, Jovana, Dimitrijević, Aleksandra, "The specificity of alpha-glucosidase from Saccharomyces cerevisiae differs depending on the type of reaction: hydrolysis versus transglucosylation" in Applied Microbiology and Biotechnology, 98, no. 14 (2014):6317-6328,
https://doi.org/10.1007/s00253-014-5587-9 . .

TY  - JOUR
AU  - Bezbradica, Dejan
AU  - Stojanović, Marija
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Carević, Milica
AU  - Mihailović, Mladen
AU  - Milosavić, Nenad
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2550
AB  - The kinetics of L-ascorbyl oleate synthesis catalyzed by immobilized lipase from Candida antarctica in acetone was investigated. Significant inhibition of synthesis with an excess of ascorbic acid was observed. Experimental data were successfully fitted with a ping-pong bi-bi kinetic model with substrate inhibition, and related kinetic constants were determined. The kinetic study was performed at optimum experimental factors (temperature, initial water content, and enzyme concentration), which were determined using response surface methodology. Then, a model for predicting product-time progress curves was developed by expanding the obtained ping-pang model with terms describing ester hydrolysis. Kinetic constants of the reverse reaction were determined, and good congruence between the model and experimental data was achieved. Calculated kinetic constants revealed that lipase has the highest affinity for ascorbyl oleate, slightly lower activity with ascorbic acid, and the lowest activity with oleic acid. The obtained results are valuable for elucidating the reaction mechanism and represent an important contribution for reaction optimization and creating strategies to increase the productivity of vitamin C ester synthesis.
PB  - Elsevier Science Sa, Lausanne
T2  - Biochemical Engineering Journal
T1  - Kinetic model of lipase-catalyzed conversion of ascorbic acid and oleic acid to liposoluble vitamin C ester
EP  - 96
SP  - 89
VL  - 71
DO  - 10.1016/j.bej.2012.12.001
ER  - 

@article{
author = "Bezbradica, Dejan and Stojanović, Marija and Veličković, Dušan and Dimitrijević, Aleksandra and Carević, Milica and Mihailović, Mladen and Milosavić, Nenad",
year = "2013",
abstract = "The kinetics of L-ascorbyl oleate synthesis catalyzed by immobilized lipase from Candida antarctica in acetone was investigated. Significant inhibition of synthesis with an excess of ascorbic acid was observed. Experimental data were successfully fitted with a ping-pong bi-bi kinetic model with substrate inhibition, and related kinetic constants were determined. The kinetic study was performed at optimum experimental factors (temperature, initial water content, and enzyme concentration), which were determined using response surface methodology. Then, a model for predicting product-time progress curves was developed by expanding the obtained ping-pang model with terms describing ester hydrolysis. Kinetic constants of the reverse reaction were determined, and good congruence between the model and experimental data was achieved. Calculated kinetic constants revealed that lipase has the highest affinity for ascorbyl oleate, slightly lower activity with ascorbic acid, and the lowest activity with oleic acid. The obtained results are valuable for elucidating the reaction mechanism and represent an important contribution for reaction optimization and creating strategies to increase the productivity of vitamin C ester synthesis.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Biochemical Engineering Journal",
title = "Kinetic model of lipase-catalyzed conversion of ascorbic acid and oleic acid to liposoluble vitamin C ester",
pages = "96-89",
volume = "71",
doi = "10.1016/j.bej.2012.12.001"
}

Bezbradica, D., Stojanović, M., Veličković, D., Dimitrijević, A., Carević, M., Mihailović, M.,& Milosavić, N.. (2013). Kinetic model of lipase-catalyzed conversion of ascorbic acid and oleic acid to liposoluble vitamin C ester. in Biochemical Engineering Journal
Elsevier Science Sa, Lausanne., 71, 89-96.
https://doi.org/10.1016/j.bej.2012.12.001

Bezbradica D, Stojanović M, Veličković D, Dimitrijević A, Carević M, Mihailović M, Milosavić N. Kinetic model of lipase-catalyzed conversion of ascorbic acid and oleic acid to liposoluble vitamin C ester. in Biochemical Engineering Journal. 2013;71:89-96.
doi:10.1016/j.bej.2012.12.001 .

Bezbradica, Dejan, Stojanović, Marija, Veličković, Dušan, Dimitrijević, Aleksandra, Carević, Milica, Mihailović, Mladen, Milosavić, Nenad, "Kinetic model of lipase-catalyzed conversion of ascorbic acid and oleic acid to liposoluble vitamin C ester" in Biochemical Engineering Journal, 71 (2013):89-96,
https://doi.org/10.1016/j.bej.2012.12.001 . .

TY  - CONF
AU  - Milisavljević, Ana
AU  - Stojanović, Marija
AU  - Dinić, Ivana
AU  - Carević, Milica
AU  - Mihailović, Mladen
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6070
AB  - Phloridzin is member of chemical class of dihydrochalcones, phenylpropanoids with
structure similar to chalcones, immediate flavonoid precursors, hence it is often classified
as flavonoid glucoside [1,2]. It is usually extracted from Malus species since it is very
abundant in young apple leaves and twigs. Due to its phenolic structure, phloridzin has
significant antioxidant activity and anti-UV properties, which makes it interesting for
application in food and cosmetics. Major limitation to wider application of phloridzin is its
low solubility in hydrophobic environment, which can be circumvented by synthesis of
physiologically active compounds derivatives by acylation of phloridzin. Synthesis of acyl
esters can be catalyzed by inorganic catalysts or enzymes, but chemical esterification is
not regioselective and results with unwanted functionalization of phenolic hydroxyl
groups responsible for antioxidative properties.
Therefore, in our study enzymatic esterification of phloridzin was performed using
immobilized lipase from Candida antarctica (Novozyme® 435). Several organic solvents
were tested and acetonitrile was proved to be the most adequate medium for this
reaction. Different acyl-donors were used with respect to chain length and saturation
level. Potential physiological activity of obtained esters was evaluated by determination of
their antioxidant activity using DPPH assay, so acyl donors were compared with respect to
both, product yields and antioxidant activity. After comparison of results of preliminary
study, phloridzyl oleate was selected as derivative with the best prospects and it used in
further experimental series for optimization of key experimental factors. Response surface
methodology was applied as statistical tool for optimization of product concentration (in
mM) as output and analyzed factors were: reaction time, temperature, enzyme
concentration, substrate molar ratio, and phloridzin concentration. After statistical
analysis each of examined experimental factors was found significant and second order
regression model was obtained. It was established that highest product concentration can
be expected at 68 oC, with 0.17 M of phloridzin, 2,5 % (w/v) of enzyme, 19-fold molar
excess of oleic acid after 7 days of reaction.
C3  - 8th International Conference of the Chemical Societies of the South-East European Countries, Belgrade, Serbia
T1  - Lipase-catalyzed synthesis of phloridzin esters
SP  - 254
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6070
ER  - 

@conference{
author = "Milisavljević, Ana and Stojanović, Marija and Dinić, Ivana and Carević, Milica and Mihailović, Mladen and Milosavić, Nenad and Bezbradica, Dejan",
year = "2013",
abstract = "Phloridzin is member of chemical class of dihydrochalcones, phenylpropanoids with
structure similar to chalcones, immediate flavonoid precursors, hence it is often classified
as flavonoid glucoside [1,2]. It is usually extracted from Malus species since it is very
abundant in young apple leaves and twigs. Due to its phenolic structure, phloridzin has
significant antioxidant activity and anti-UV properties, which makes it interesting for
application in food and cosmetics. Major limitation to wider application of phloridzin is its
low solubility in hydrophobic environment, which can be circumvented by synthesis of
physiologically active compounds derivatives by acylation of phloridzin. Synthesis of acyl
esters can be catalyzed by inorganic catalysts or enzymes, but chemical esterification is
not regioselective and results with unwanted functionalization of phenolic hydroxyl
groups responsible for antioxidative properties.
Therefore, in our study enzymatic esterification of phloridzin was performed using
immobilized lipase from Candida antarctica (Novozyme® 435). Several organic solvents
were tested and acetonitrile was proved to be the most adequate medium for this
reaction. Different acyl-donors were used with respect to chain length and saturation
level. Potential physiological activity of obtained esters was evaluated by determination of
their antioxidant activity using DPPH assay, so acyl donors were compared with respect to
both, product yields and antioxidant activity. After comparison of results of preliminary
study, phloridzyl oleate was selected as derivative with the best prospects and it used in
further experimental series for optimization of key experimental factors. Response surface
methodology was applied as statistical tool for optimization of product concentration (in
mM) as output and analyzed factors were: reaction time, temperature, enzyme
concentration, substrate molar ratio, and phloridzin concentration. After statistical
analysis each of examined experimental factors was found significant and second order
regression model was obtained. It was established that highest product concentration can
be expected at 68 oC, with 0.17 M of phloridzin, 2,5 % (w/v) of enzyme, 19-fold molar
excess of oleic acid after 7 days of reaction.",
journal = "8th International Conference of the Chemical Societies of the South-East European Countries, Belgrade, Serbia",
title = "Lipase-catalyzed synthesis of phloridzin esters",
pages = "254",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6070"
}

Milisavljević, A., Stojanović, M., Dinić, I., Carević, M., Mihailović, M., Milosavić, N.,& Bezbradica, D.. (2013). Lipase-catalyzed synthesis of phloridzin esters. in 8th International Conference of the Chemical Societies of the South-East European Countries, Belgrade, Serbia, 254.
https://hdl.handle.net/21.15107/rcub_technorep_6070

Milisavljević A, Stojanović M, Dinić I, Carević M, Mihailović M, Milosavić N, Bezbradica D. Lipase-catalyzed synthesis of phloridzin esters. in 8th International Conference of the Chemical Societies of the South-East European Countries, Belgrade, Serbia. 2013;:254.
https://hdl.handle.net/21.15107/rcub_technorep_6070 .

Milisavljević, Ana, Stojanović, Marija, Dinić, Ivana, Carević, Milica, Mihailović, Mladen, Milosavić, Nenad, Bezbradica, Dejan, "Lipase-catalyzed synthesis of phloridzin esters" in 8th International Conference of the Chemical Societies of the South-East European Countries, Belgrade, Serbia (2013):254,
https://hdl.handle.net/21.15107/rcub_technorep_6070 .

TY  - JOUR
AU  - Stojanović, Marija
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Milosavić, Nenad
AU  - Knežević-Jugović, Zorica
AU  - Bezbradica, Dejan
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2413
AB  - Lipase-catalyzed ascorbyl oleate synthesis is eco-friendly and selective way of production of liposoluble biocompatible antioxidants, but still not present on an industrial level due to the high biocatalyst costs. In this study, response surface methodology was applied in order to estimate influence of individual experimental factors, identify interactions among them, and to determine optimum conditions for enzymatic synthesis of ascorbyl oleate in acetone, in terms of limiting substrate conversion, product yield, and yield per mass of consumed enzyme. As a biocatalyst, commercial immobilized preparation of lipase B from Candida antarctica, Novozym 435, was used. In order to develop cost-effective process, at reaction conditions at which maximum amount of product per mass of biocatalyst was produced (60 degrees C, 0.018 % (v/v) of water, 0.135 M of vitamin C, substrates molar ratio 1:8, and 0.2 % (w/v) of lipase), possibilities for further increase of ester yield were investigated. Addition of molecular sieves at 4th hour of reaction enabled increase of yield from 16.7 mmol g(-1) to 19.3 mmol g(-1). Operational stability study revealed that after ten reaction cycles enzyme retained 48 % of its initial activity. Optimized synthesis with well-timed molecular sieves addition and repeated use of lipase provided production of 153 mmol per gram of enzyme. Further improvement of productivity was achieved using procedure for the enzyme reactivation.
PB  - Japan Oil Chemists Soc, Tokyo
T2  - Journal of Oleo Science
T1  - Lipase-Catalyzed Synthesis of Ascorbyl Oleate in Acetone: Optimization of Reaction Conditions and Lipase Reusability
EP  - 603
IS  - 8
SP  - 591
VL  - 62
DO  - 10.5650/jos.62.591
ER  - 

@article{
author = "Stojanović, Marija and Veličković, Dušan and Dimitrijević, Aleksandra and Milosavić, Nenad and Knežević-Jugović, Zorica and Bezbradica, Dejan",
year = "2013",
abstract = "Lipase-catalyzed ascorbyl oleate synthesis is eco-friendly and selective way of production of liposoluble biocompatible antioxidants, but still not present on an industrial level due to the high biocatalyst costs. In this study, response surface methodology was applied in order to estimate influence of individual experimental factors, identify interactions among them, and to determine optimum conditions for enzymatic synthesis of ascorbyl oleate in acetone, in terms of limiting substrate conversion, product yield, and yield per mass of consumed enzyme. As a biocatalyst, commercial immobilized preparation of lipase B from Candida antarctica, Novozym 435, was used. In order to develop cost-effective process, at reaction conditions at which maximum amount of product per mass of biocatalyst was produced (60 degrees C, 0.018 % (v/v) of water, 0.135 M of vitamin C, substrates molar ratio 1:8, and 0.2 % (w/v) of lipase), possibilities for further increase of ester yield were investigated. Addition of molecular sieves at 4th hour of reaction enabled increase of yield from 16.7 mmol g(-1) to 19.3 mmol g(-1). Operational stability study revealed that after ten reaction cycles enzyme retained 48 % of its initial activity. Optimized synthesis with well-timed molecular sieves addition and repeated use of lipase provided production of 153 mmol per gram of enzyme. Further improvement of productivity was achieved using procedure for the enzyme reactivation.",
publisher = "Japan Oil Chemists Soc, Tokyo",
journal = "Journal of Oleo Science",
title = "Lipase-Catalyzed Synthesis of Ascorbyl Oleate in Acetone: Optimization of Reaction Conditions and Lipase Reusability",
pages = "603-591",
number = "8",
volume = "62",
doi = "10.5650/jos.62.591"
}

Stojanović, M., Veličković, D., Dimitrijević, A., Milosavić, N., Knežević-Jugović, Z.,& Bezbradica, D.. (2013). Lipase-Catalyzed Synthesis of Ascorbyl Oleate in Acetone: Optimization of Reaction Conditions and Lipase Reusability. in Journal of Oleo Science
Japan Oil Chemists Soc, Tokyo., 62(8), 591-603.
https://doi.org/10.5650/jos.62.591

Stojanović M, Veličković D, Dimitrijević A, Milosavić N, Knežević-Jugović Z, Bezbradica D. Lipase-Catalyzed Synthesis of Ascorbyl Oleate in Acetone: Optimization of Reaction Conditions and Lipase Reusability. in Journal of Oleo Science. 2013;62(8):591-603.
doi:10.5650/jos.62.591 .

Stojanović, Marija, Veličković, Dušan, Dimitrijević, Aleksandra, Milosavić, Nenad, Knežević-Jugović, Zorica, Bezbradica, Dejan, "Lipase-Catalyzed Synthesis of Ascorbyl Oleate in Acetone: Optimization of Reaction Conditions and Lipase Reusability" in Journal of Oleo Science, 62, no. 8 (2013):591-603,
https://doi.org/10.5650/jos.62.591 . .

TY  - JOUR
AU  - Pavlović, Marijana
AU  - Dimitrijević, Aleksandra
AU  - Trbojević-Ivić, Jovana
AU  - Milosavić, Nenad
AU  - Gavrović-Jankulović, Marija
AU  - Bezbradica, Dejan
AU  - Veličković, Dušan
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2448
AB  - alpha-1,4-Glucosidase from Saccharomyces cerevisiae is an enzyme which is widely used in synthesis of different drugs. Glucosidase inhibitors are studied as potential drugs for prevention of HIV and diabetes. For understanding of these processes it is very important to have insights in the transglucosylation activity of this enzyme. In this paper the kinetics of transglucosylation reaction catalyzed by this enzyme in the synthesis of benzyl alcohol glucoside was studied and all relevant kinetic constants for this system are found. It was shown one additional property of transglycosylation reactions catalyzed by glycosidases-inhibition by both, glucose acceptor and glucose donor, and mechanisms for these inhibitions were proposed.
PB  - Maik Nauka/Interperiodica/Springer, New York
T2  - Russian Journal of Physical Chemistry A
T1  - A study of transglucosylation kinetic in an enzymatic synthesis of benzyl alcohol glucoside by alpha-glucosidase from S-cerevisiae
EP  - 2288
IS  - 13
SP  - 2285
VL  - 87
DO  - 10.1134/S0036024413130207
ER  - 

@article{
author = "Pavlović, Marijana and Dimitrijević, Aleksandra and Trbojević-Ivić, Jovana and Milosavić, Nenad and Gavrović-Jankulović, Marija and Bezbradica, Dejan and Veličković, Dušan",
year = "2013",
abstract = "alpha-1,4-Glucosidase from Saccharomyces cerevisiae is an enzyme which is widely used in synthesis of different drugs. Glucosidase inhibitors are studied as potential drugs for prevention of HIV and diabetes. For understanding of these processes it is very important to have insights in the transglucosylation activity of this enzyme. In this paper the kinetics of transglucosylation reaction catalyzed by this enzyme in the synthesis of benzyl alcohol glucoside was studied and all relevant kinetic constants for this system are found. It was shown one additional property of transglycosylation reactions catalyzed by glycosidases-inhibition by both, glucose acceptor and glucose donor, and mechanisms for these inhibitions were proposed.",
publisher = "Maik Nauka/Interperiodica/Springer, New York",
journal = "Russian Journal of Physical Chemistry A",
title = "A study of transglucosylation kinetic in an enzymatic synthesis of benzyl alcohol glucoside by alpha-glucosidase from S-cerevisiae",
pages = "2288-2285",
number = "13",
volume = "87",
doi = "10.1134/S0036024413130207"
}

Pavlović, M., Dimitrijević, A., Trbojević-Ivić, J., Milosavić, N., Gavrović-Jankulović, M., Bezbradica, D.,& Veličković, D.. (2013). A study of transglucosylation kinetic in an enzymatic synthesis of benzyl alcohol glucoside by alpha-glucosidase from S-cerevisiae. in Russian Journal of Physical Chemistry A
Maik Nauka/Interperiodica/Springer, New York., 87(13), 2285-2288.
https://doi.org/10.1134/S0036024413130207

Pavlović M, Dimitrijević A, Trbojević-Ivić J, Milosavić N, Gavrović-Jankulović M, Bezbradica D, Veličković D. A study of transglucosylation kinetic in an enzymatic synthesis of benzyl alcohol glucoside by alpha-glucosidase from S-cerevisiae. in Russian Journal of Physical Chemistry A. 2013;87(13):2285-2288.
doi:10.1134/S0036024413130207 .

Pavlović, Marijana, Dimitrijević, Aleksandra, Trbojević-Ivić, Jovana, Milosavić, Nenad, Gavrović-Jankulović, Marija, Bezbradica, Dejan, Veličković, Dušan, "A study of transglucosylation kinetic in an enzymatic synthesis of benzyl alcohol glucoside by alpha-glucosidase from S-cerevisiae" in Russian Journal of Physical Chemistry A, 87, no. 13 (2013):2285-2288,
https://doi.org/10.1134/S0036024413130207 . .

TY  - CONF
AU  - Stojanović, M.M.
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Milosavić, Nenad
AU  - Knežević-Jugović, Zorica
AU  - Bezbradica, Dejan
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1976
AB  - L-ascorbic acid has good antioxidative properties but its efficiency in stabilizing fats and oils in products with high lipid content is negligible due to its hydrophilic characteristics. On the other hand, fatty acid ascorbyl esters are liposoluble, with even better antioxidative properties comparing to L-ascorbic acid. Therefore, developing of industrial process for lipase-catalyzed synthesis of vitamin C fatty acid esters, considering numerous advantages over conventional chemical methods (mild reaction conditions, high regioselectivity, and simplified downstream processing), is of great interest. In this study, L-ascorbyl oleate was synthesized in esterification reaction between vitamin C and oleic acid catalyzed by immobilized lipase from Candida antarctica in acetone as a reaction medium. Response surface methodology and 5-level-5-factor central composite rotatable design were employed in order to investigate interactions between experimental factors (initial water content, temperature, substrates molar ratio, vitamin C concentration, and enzyme amount), determine their individual influence on molar conversion, and eventually optimize the synthesis. Based on the experimental data, regression model, expressed with second order polynomial equation, was obtained. At values in the range of examination, enzyme amount had no influence on conversion so it was fixed at the minimum (0.2 % (w/v)). The maximum molar conversion of 91.3 % was predicted and corresponding, optimal reaction conditions were: temperature - 60 °C, initial water content - 0 % (v/v), vitamin C concentration - 0.02 M, and substrate molar ratio - 1:15. Our system provided reaction conditions which enabled high conversions, thus obtained results may be used as a starting point for the process scale-up.
PB  - 6th Central European Congress on Food, CEFood 2012
C3  - CEFood 2012 - Proceedings of 6th Central European Congress on Food
T1  - Study of lipase-catalyzed synthesis of ascorbyl oleate using response surface methodology
EP  - 813
SP  - 807
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1976
ER  - 

@conference{
author = "Stojanović, M.M. and Veličković, Dušan and Dimitrijević, Aleksandra and Milosavić, Nenad and Knežević-Jugović, Zorica and Bezbradica, Dejan",
year = "2012",
abstract = "L-ascorbic acid has good antioxidative properties but its efficiency in stabilizing fats and oils in products with high lipid content is negligible due to its hydrophilic characteristics. On the other hand, fatty acid ascorbyl esters are liposoluble, with even better antioxidative properties comparing to L-ascorbic acid. Therefore, developing of industrial process for lipase-catalyzed synthesis of vitamin C fatty acid esters, considering numerous advantages over conventional chemical methods (mild reaction conditions, high regioselectivity, and simplified downstream processing), is of great interest. In this study, L-ascorbyl oleate was synthesized in esterification reaction between vitamin C and oleic acid catalyzed by immobilized lipase from Candida antarctica in acetone as a reaction medium. Response surface methodology and 5-level-5-factor central composite rotatable design were employed in order to investigate interactions between experimental factors (initial water content, temperature, substrates molar ratio, vitamin C concentration, and enzyme amount), determine their individual influence on molar conversion, and eventually optimize the synthesis. Based on the experimental data, regression model, expressed with second order polynomial equation, was obtained. At values in the range of examination, enzyme amount had no influence on conversion so it was fixed at the minimum (0.2 % (w/v)). The maximum molar conversion of 91.3 % was predicted and corresponding, optimal reaction conditions were: temperature - 60 °C, initial water content - 0 % (v/v), vitamin C concentration - 0.02 M, and substrate molar ratio - 1:15. Our system provided reaction conditions which enabled high conversions, thus obtained results may be used as a starting point for the process scale-up.",
publisher = "6th Central European Congress on Food, CEFood 2012",
journal = "CEFood 2012 - Proceedings of 6th Central European Congress on Food",
title = "Study of lipase-catalyzed synthesis of ascorbyl oleate using response surface methodology",
pages = "813-807",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1976"
}

Stojanović, M.M., Veličković, D., Dimitrijević, A., Milosavić, N., Knežević-Jugović, Z.,& Bezbradica, D.. (2012). Study of lipase-catalyzed synthesis of ascorbyl oleate using response surface methodology. in CEFood 2012 - Proceedings of 6th Central European Congress on Food
6th Central European Congress on Food, CEFood 2012., 807-813.
https://hdl.handle.net/21.15107/rcub_technorep_1976

Stojanović M, Veličković D, Dimitrijević A, Milosavić N, Knežević-Jugović Z, Bezbradica D. Study of lipase-catalyzed synthesis of ascorbyl oleate using response surface methodology. in CEFood 2012 - Proceedings of 6th Central European Congress on Food. 2012;:807-813.
https://hdl.handle.net/21.15107/rcub_technorep_1976 .

Stojanović, M.M., Veličković, Dušan, Dimitrijević, Aleksandra, Milosavić, Nenad, Knežević-Jugović, Zorica, Bezbradica, Dejan, "Study of lipase-catalyzed synthesis of ascorbyl oleate using response surface methodology" in CEFood 2012 - Proceedings of 6th Central European Congress on Food (2012):807-813,
https://hdl.handle.net/21.15107/rcub_technorep_1976 .

TY  - CHAP
AU  - Milosavić, Nenad
AU  - Dimitrijević, Aleksandra
AU  - Veličković, Dušan
AU  - Bezbradica, Dejan
AU  - Knežević-Jugović, Zorica
AU  - Jankov, Ratko
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1968
AB  - Enzymes are a particularly versatile class of catalysts that perform and regulate processes in living matter. Enzymatic regio-, chemo- and enantioselectivity were used in industry and in organic synthesis. The common perception is however, that enzymes are sensitive, unstable and have to be used in water, features that are not ideal for a catalyst and undesirable in most syntheses. In many cases a way to avoid at least part of these complaints is to immobilize enzymes. There are several immobilization techniques, and the best means of avoiding any negative influence on the structure of an enzyme is to encapsulate it. Due to its ability to form gel with multivalent cations under relatively mild conditions, alginates are very important in cell and enzyme encapsulation. Entrapment within insoluble alginate gel is recognized as a rapid, nontoxic, inexpensive and versatile method for immobilization of enzymes as well as cells. The resultant gel is biochemically inert and mechanically stable with interstitial spaces that are suitable for cell immobilization.
T2  - Alginates: Production, Types and Applications
T1  - Application of alginates in cell and enzyme immobilization
EP  - 60
SP  - 37
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1968
ER  - 

@inbook{
author = "Milosavić, Nenad and Dimitrijević, Aleksandra and Veličković, Dušan and Bezbradica, Dejan and Knežević-Jugović, Zorica and Jankov, Ratko",
year = "2012",
abstract = "Enzymes are a particularly versatile class of catalysts that perform and regulate processes in living matter. Enzymatic regio-, chemo- and enantioselectivity were used in industry and in organic synthesis. The common perception is however, that enzymes are sensitive, unstable and have to be used in water, features that are not ideal for a catalyst and undesirable in most syntheses. In many cases a way to avoid at least part of these complaints is to immobilize enzymes. There are several immobilization techniques, and the best means of avoiding any negative influence on the structure of an enzyme is to encapsulate it. Due to its ability to form gel with multivalent cations under relatively mild conditions, alginates are very important in cell and enzyme encapsulation. Entrapment within insoluble alginate gel is recognized as a rapid, nontoxic, inexpensive and versatile method for immobilization of enzymes as well as cells. The resultant gel is biochemically inert and mechanically stable with interstitial spaces that are suitable for cell immobilization.",
journal = "Alginates: Production, Types and Applications",
booktitle = "Application of alginates in cell and enzyme immobilization",
pages = "60-37",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1968"
}

Milosavić, N., Dimitrijević, A., Veličković, D., Bezbradica, D., Knežević-Jugović, Z.,& Jankov, R.. (2012). Application of alginates in cell and enzyme immobilization. in Alginates: Production, Types and Applications, 37-60.
https://hdl.handle.net/21.15107/rcub_technorep_1968

Milosavić N, Dimitrijević A, Veličković D, Bezbradica D, Knežević-Jugović Z, Jankov R. Application of alginates in cell and enzyme immobilization. in Alginates: Production, Types and Applications. 2012;:37-60.
https://hdl.handle.net/21.15107/rcub_technorep_1968 .

Milosavić, Nenad, Dimitrijević, Aleksandra, Veličković, Dušan, Bezbradica, Dejan, Knežević-Jugović, Zorica, Jankov, Ratko, "Application of alginates in cell and enzyme immobilization" in Alginates: Production, Types and Applications (2012):37-60,
https://hdl.handle.net/21.15107/rcub_technorep_1968 .

TY  - JOUR
AU  - Dimitrijević, Aleksandra
AU  - Veličković, Dušan
AU  - Bihelović, Filip
AU  - Bezbradica, Dejan
AU  - Jankov, Ratko
AU  - Milosavić, Nenad
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2201
AB  - Lipase A from Candida antarctica (CAL A) was purified to apparent homogeneity in a single step using hydroxyapatite (HAP) chromatography. CAL A bound to HAP was eluted with 10 mM Na-phosphate buffer, pH 7.0 containing 0.5% Triton X-100. The protocol resulted in a 3.74-fold purification with 94.7% final recovery and 400.83 U/mg specific activity. Silver staining after SDS-PAGE revealed the presence a single band of 45 kDa. The enzyme exhibited a temperature optimum of 60 degrees C, was unaffected by monovalent metal ions, but was destabilized by divalent metal ions (Zn2+, Ca2+, Mg2+, Cu2+, Mn2+) and stimulated by 50 mM Fe2+. Detergents at 0.1% concentrations did not affect lipase activity. Except for Triton X-100, detergent concentrations of 1% had a destabilizing effect.
PB  - Elsevier Sci Ltd, Oxford
T2  - Bioresource Technology
T1  - One-step, inexpensive high yield strategy for Candida antarctica lipase A isolation using hydroxyapatite
EP  - 362
SP  - 358
VL  - 107
DO  - 10.1016/j.biortech.2011.11.077
ER  - 

@article{
author = "Dimitrijević, Aleksandra and Veličković, Dušan and Bihelović, Filip and Bezbradica, Dejan and Jankov, Ratko and Milosavić, Nenad",
year = "2012",
abstract = "Lipase A from Candida antarctica (CAL A) was purified to apparent homogeneity in a single step using hydroxyapatite (HAP) chromatography. CAL A bound to HAP was eluted with 10 mM Na-phosphate buffer, pH 7.0 containing 0.5% Triton X-100. The protocol resulted in a 3.74-fold purification with 94.7% final recovery and 400.83 U/mg specific activity. Silver staining after SDS-PAGE revealed the presence a single band of 45 kDa. The enzyme exhibited a temperature optimum of 60 degrees C, was unaffected by monovalent metal ions, but was destabilized by divalent metal ions (Zn2+, Ca2+, Mg2+, Cu2+, Mn2+) and stimulated by 50 mM Fe2+. Detergents at 0.1% concentrations did not affect lipase activity. Except for Triton X-100, detergent concentrations of 1% had a destabilizing effect.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Bioresource Technology",
title = "One-step, inexpensive high yield strategy for Candida antarctica lipase A isolation using hydroxyapatite",
pages = "362-358",
volume = "107",
doi = "10.1016/j.biortech.2011.11.077"
}

Dimitrijević, A., Veličković, D., Bihelović, F., Bezbradica, D., Jankov, R.,& Milosavić, N.. (2012). One-step, inexpensive high yield strategy for Candida antarctica lipase A isolation using hydroxyapatite. in Bioresource Technology
Elsevier Sci Ltd, Oxford., 107, 358-362.
https://doi.org/10.1016/j.biortech.2011.11.077

Dimitrijević A, Veličković D, Bihelović F, Bezbradica D, Jankov R, Milosavić N. One-step, inexpensive high yield strategy for Candida antarctica lipase A isolation using hydroxyapatite. in Bioresource Technology. 2012;107:358-362.
doi:10.1016/j.biortech.2011.11.077 .

Dimitrijević, Aleksandra, Veličković, Dušan, Bihelović, Filip, Bezbradica, Dejan, Jankov, Ratko, Milosavić, Nenad, "One-step, inexpensive high yield strategy for Candida antarctica lipase A isolation using hydroxyapatite" in Bioresource Technology, 107 (2012):358-362,
https://doi.org/10.1016/j.biortech.2011.11.077 . .

TY  - JOUR
AU  - Dimitrijević, Aleksandra
AU  - Veličković, Dušan
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2157
AB  - Vanillyl alcohol glucoside is very attractive molecule due to its very powerful physiological activity. In this article, a detailed kinetic study of transglucosylation of vanillyl alcohol was performed. It was demonstrated that this reaction is very efficient (selectivity factor is 149) and occurred by a ping-pong mechanism with inhibition by glucose acceptor. At low concentration of vanillyl alcohol one additional transglucosylation product was detected. Its structure was determined to be a-isomaltoside of vanillyl alcohol, indicating that vanillyl alcohol glucoside is a product of the first transglucosylation reaction and a substrate for second, so the whole reaction mechanism was proposed. It was demonstrated that the rate of isomaltoside synthesis is two orders of magnitude smaller than glucoside synthesis, and that maltase has interestingly high Km value to maltose when vanillyl alcohol glucoside is second transglucosylation substrate.
PB  - Wiley, Hoboken
T2  - Biotechnology Progress
T1  - Specificity of maltase to maltose in three different directions of reaction: Hydrolytic, vanillyl alcohol glucoside and vanillyl alcohol isomaltoside synthesis
EP  - 1456
IS  - 6
SP  - 1450
VL  - 28
DO  - 10.1002/btpr.1628
ER  - 

@article{
author = "Dimitrijević, Aleksandra and Veličković, Dušan and Milosavić, Nenad and Bezbradica, Dejan",
year = "2012",
abstract = "Vanillyl alcohol glucoside is very attractive molecule due to its very powerful physiological activity. In this article, a detailed kinetic study of transglucosylation of vanillyl alcohol was performed. It was demonstrated that this reaction is very efficient (selectivity factor is 149) and occurred by a ping-pong mechanism with inhibition by glucose acceptor. At low concentration of vanillyl alcohol one additional transglucosylation product was detected. Its structure was determined to be a-isomaltoside of vanillyl alcohol, indicating that vanillyl alcohol glucoside is a product of the first transglucosylation reaction and a substrate for second, so the whole reaction mechanism was proposed. It was demonstrated that the rate of isomaltoside synthesis is two orders of magnitude smaller than glucoside synthesis, and that maltase has interestingly high Km value to maltose when vanillyl alcohol glucoside is second transglucosylation substrate.",
publisher = "Wiley, Hoboken",
journal = "Biotechnology Progress",
title = "Specificity of maltase to maltose in three different directions of reaction: Hydrolytic, vanillyl alcohol glucoside and vanillyl alcohol isomaltoside synthesis",
pages = "1456-1450",
number = "6",
volume = "28",
doi = "10.1002/btpr.1628"
}

Dimitrijević, A., Veličković, D., Milosavić, N.,& Bezbradica, D.. (2012). Specificity of maltase to maltose in three different directions of reaction: Hydrolytic, vanillyl alcohol glucoside and vanillyl alcohol isomaltoside synthesis. in Biotechnology Progress
Wiley, Hoboken., 28(6), 1450-1456.
https://doi.org/10.1002/btpr.1628

Dimitrijević A, Veličković D, Milosavić N, Bezbradica D. Specificity of maltase to maltose in three different directions of reaction: Hydrolytic, vanillyl alcohol glucoside and vanillyl alcohol isomaltoside synthesis. in Biotechnology Progress. 2012;28(6):1450-1456.
doi:10.1002/btpr.1628 .

Dimitrijević, Aleksandra, Veličković, Dušan, Milosavić, Nenad, Bezbradica, Dejan, "Specificity of maltase to maltose in three different directions of reaction: Hydrolytic, vanillyl alcohol glucoside and vanillyl alcohol isomaltoside synthesis" in Biotechnology Progress, 28, no. 6 (2012):1450-1456,
https://doi.org/10.1002/btpr.1628 . .

TY  - JOUR
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Bihelović, Filip
AU  - Bezbradica, Dejan
AU  - Knežević-Jugović, Zorica
AU  - Milosavić, Nenad
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2109
AB  - Novel glucoside of physiological active vanillyl alcohol was synthesized for the first time using maltase from Saccharomyces cerevisiae as catalyst, and established its structure as 4-hydroxy-3-methoxybenzyl-alpha-d-glucopyranoside. The key reaction factors for this transglucosylation reaction were optimized using response surface methodology and the highest yield so far in maltase catalyzed transglucosylation reaction was obtained. It was found out that optimum temperature of reaction was 37 A degrees C, optimal maltose concentration was 60% (w/v), optimal pH was 6.6, and optimal concentration of vanillyl alcohol was 158 mM. Under these conditions, yield of glucoside was 90 mM with no by product formation. It was shown that this compound posses good antioxidant activity as well as stability in gastrointestinal tract. It was demonstrated that it is hydrolyzed on brush border membrane of enterocytes, so it can serve in protecting gastrointestinal system from oxidation, as well as source of anticonvulsive drug after the hydrolysis of glucoside on brush border membrane of small intestine.
PB  - Springer, New York
T2  - Bioprocess and Biosystems Engineering
T1  - Novel glycoside of vanillyl alcohol, 4-hydroxy-3-methoxybenzyl-alpha-d-glucopyranoside: study of enzymatic synthesis, in vitro digestion and antioxidant activity
EP  - 1115
IS  - 7
SP  - 1107
VL  - 35
DO  - 10.1007/s00449-012-0695-3
ER  - 

@article{
author = "Veličković, Dušan and Dimitrijević, Aleksandra and Bihelović, Filip and Bezbradica, Dejan and Knežević-Jugović, Zorica and Milosavić, Nenad",
year = "2012",
abstract = "Novel glucoside of physiological active vanillyl alcohol was synthesized for the first time using maltase from Saccharomyces cerevisiae as catalyst, and established its structure as 4-hydroxy-3-methoxybenzyl-alpha-d-glucopyranoside. The key reaction factors for this transglucosylation reaction were optimized using response surface methodology and the highest yield so far in maltase catalyzed transglucosylation reaction was obtained. It was found out that optimum temperature of reaction was 37 A degrees C, optimal maltose concentration was 60% (w/v), optimal pH was 6.6, and optimal concentration of vanillyl alcohol was 158 mM. Under these conditions, yield of glucoside was 90 mM with no by product formation. It was shown that this compound posses good antioxidant activity as well as stability in gastrointestinal tract. It was demonstrated that it is hydrolyzed on brush border membrane of enterocytes, so it can serve in protecting gastrointestinal system from oxidation, as well as source of anticonvulsive drug after the hydrolysis of glucoside on brush border membrane of small intestine.",
publisher = "Springer, New York",
journal = "Bioprocess and Biosystems Engineering",
title = "Novel glycoside of vanillyl alcohol, 4-hydroxy-3-methoxybenzyl-alpha-d-glucopyranoside: study of enzymatic synthesis, in vitro digestion and antioxidant activity",
pages = "1115-1107",
number = "7",
volume = "35",
doi = "10.1007/s00449-012-0695-3"
}

Veličković, D., Dimitrijević, A., Bihelović, F., Bezbradica, D., Knežević-Jugović, Z.,& Milosavić, N.. (2012). Novel glycoside of vanillyl alcohol, 4-hydroxy-3-methoxybenzyl-alpha-d-glucopyranoside: study of enzymatic synthesis, in vitro digestion and antioxidant activity. in Bioprocess and Biosystems Engineering
Springer, New York., 35(7), 1107-1115.
https://doi.org/10.1007/s00449-012-0695-3

Veličković D, Dimitrijević A, Bihelović F, Bezbradica D, Knežević-Jugović Z, Milosavić N. Novel glycoside of vanillyl alcohol, 4-hydroxy-3-methoxybenzyl-alpha-d-glucopyranoside: study of enzymatic synthesis, in vitro digestion and antioxidant activity. in Bioprocess and Biosystems Engineering. 2012;35(7):1107-1115.
doi:10.1007/s00449-012-0695-3 .

Veličković, Dušan, Dimitrijević, Aleksandra, Bihelović, Filip, Bezbradica, Dejan, Knežević-Jugović, Zorica, Milosavić, Nenad, "Novel glycoside of vanillyl alcohol, 4-hydroxy-3-methoxybenzyl-alpha-d-glucopyranoside: study of enzymatic synthesis, in vitro digestion and antioxidant activity" in Bioprocess and Biosystems Engineering, 35, no. 7 (2012):1107-1115,
https://doi.org/10.1007/s00449-012-0695-3 . .

TY  - JOUR
AU  - Dimitrijević, Aleksandra
AU  - Veličković, Dušan
AU  - Bezbradica, Dejan
AU  - Bihelović, Filip
AU  - Jankov, Ratko
AU  - Milosavić, Nenad
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1800
AB  - The production of lipase from Pseudozyma aphidis (DSM 70725) was determined in six different media. The highest lipase production was observed in a medium with glucose as the sole carbon source, and yeast extract and sodium nitrate as the nitrogen sources. The time course studies of growth and lipase production in the optimal medium revealed that the highest lipase production was achieved at the end of the log phase of growth, reaching the value of 35.0 U cm-3 in the fifth day of cultivation. The effects of various polar, water-miscible, organic solvents on the activity and stability of the crude lipase produced by P. aphidis were evaluated. The hydrolytic activity of the crude lipase towards p-nitrophenyl palmitate (p-NPP) in aqueous media and in organic solvents was determined, using the same spectrophotometric assay in both the aqueous and organic media. The crude lipase preparation exhibited activity towards p-NPP only in acetone and acetonitrile, while the lipase was stable only in acetone, with 23% residual activity after 24 h of incubation. These results suggested that lipase from P. aphidis can be used as a biocatalyst for potential applications in such organic solvents.
AB  - Proizvodnja lipaze iz Pseudozyma aphidis utvrđena je u šest različitih medijuma. Najviša proizvodnja uočena je u medijumu gde je glukoza bila izvor ugljenika, a ekstrakt kvasca i natrijum-nitrat izvori azota. Praćenjem dinamike rasta i proizvodnje lipaze u optimalnom medijumu, uočeno je da se najviša proizvodnja lipaze dostiže pred kraj logaritamske faze rasta, i dostiže vrednost od 35 U cm-3 u petom danu kultivacije, što je četri puta veća proizvodnja od one do sada prijavljene u literaturi. Utvrđen je efekat različitih polarnih organskih rastvarača, mešljivih sa vodom, na aktivnost i stabilnost lipaze iz P. aphidis. Hidrolitička aktivnost lipaze prema para-nitrofenil-palmitatu (p-NPP-u) u vo- denoj sredini i organskim rastvaračima utvrđena je upotrebom istog spektrofotometrijskog testa. Pokazano je da lipaza ima aktivnost prema p-NPP-u samo u acetonu i acetonitrilu, dok je enzim stabilan jedino u acetonu i zadržava 23% aktivnosti nakon 24 časa inkubacije. Dobijeni rezultati ukazuju da lipaza iz P. aphidis može biti korišćena kao biokatalizator za potencijalne primene u acetonu kao medijumu.
PB  - Serbian Chemical Society, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - Production of lipase from Pseudozyma aphidis and determination of the activity and stability of the crude lipase preparation in polar organic solvents
T1  - Proizvodnja lipaze iz Pseudozyma aphidis i utvrđivanje aktivnosti i stabilnosti lipaze u polarnim organskim rastvaračima
EP  - 1092
IS  - 8
SP  - 1081
VL  - 76
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1800
ER  - 

@article{
author = "Dimitrijević, Aleksandra and Veličković, Dušan and Bezbradica, Dejan and Bihelović, Filip and Jankov, Ratko and Milosavić, Nenad",
year = "2011",
abstract = "The production of lipase from Pseudozyma aphidis (DSM 70725) was determined in six different media. The highest lipase production was observed in a medium with glucose as the sole carbon source, and yeast extract and sodium nitrate as the nitrogen sources. The time course studies of growth and lipase production in the optimal medium revealed that the highest lipase production was achieved at the end of the log phase of growth, reaching the value of 35.0 U cm-3 in the fifth day of cultivation. The effects of various polar, water-miscible, organic solvents on the activity and stability of the crude lipase produced by P. aphidis were evaluated. The hydrolytic activity of the crude lipase towards p-nitrophenyl palmitate (p-NPP) in aqueous media and in organic solvents was determined, using the same spectrophotometric assay in both the aqueous and organic media. The crude lipase preparation exhibited activity towards p-NPP only in acetone and acetonitrile, while the lipase was stable only in acetone, with 23% residual activity after 24 h of incubation. These results suggested that lipase from P. aphidis can be used as a biocatalyst for potential applications in such organic solvents., Proizvodnja lipaze iz Pseudozyma aphidis utvrđena je u šest različitih medijuma. Najviša proizvodnja uočena je u medijumu gde je glukoza bila izvor ugljenika, a ekstrakt kvasca i natrijum-nitrat izvori azota. Praćenjem dinamike rasta i proizvodnje lipaze u optimalnom medijumu, uočeno je da se najviša proizvodnja lipaze dostiže pred kraj logaritamske faze rasta, i dostiže vrednost od 35 U cm-3 u petom danu kultivacije, što je četri puta veća proizvodnja od one do sada prijavljene u literaturi. Utvrđen je efekat različitih polarnih organskih rastvarača, mešljivih sa vodom, na aktivnost i stabilnost lipaze iz P. aphidis. Hidrolitička aktivnost lipaze prema para-nitrofenil-palmitatu (p-NPP-u) u vo- denoj sredini i organskim rastvaračima utvrđena je upotrebom istog spektrofotometrijskog testa. Pokazano je da lipaza ima aktivnost prema p-NPP-u samo u acetonu i acetonitrilu, dok je enzim stabilan jedino u acetonu i zadržava 23% aktivnosti nakon 24 časa inkubacije. Dobijeni rezultati ukazuju da lipaza iz P. aphidis može biti korišćena kao biokatalizator za potencijalne primene u acetonu kao medijumu.",
publisher = "Serbian Chemical Society, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "Production of lipase from Pseudozyma aphidis and determination of the activity and stability of the crude lipase preparation in polar organic solvents, Proizvodnja lipaze iz Pseudozyma aphidis i utvrđivanje aktivnosti i stabilnosti lipaze u polarnim organskim rastvaračima",
pages = "1092-1081",
number = "8",
volume = "76",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1800"
}

Dimitrijević, A., Veličković, D., Bezbradica, D., Bihelović, F., Jankov, R.,& Milosavić, N.. (2011). Production of lipase from Pseudozyma aphidis and determination of the activity and stability of the crude lipase preparation in polar organic solvents. in Journal of the Serbian Chemical Society
Serbian Chemical Society, Belgrade., 76(8), 1081-1092.
https://hdl.handle.net/21.15107/rcub_technorep_1800

Dimitrijević A, Veličković D, Bezbradica D, Bihelović F, Jankov R, Milosavić N. Production of lipase from Pseudozyma aphidis and determination of the activity and stability of the crude lipase preparation in polar organic solvents. in Journal of the Serbian Chemical Society. 2011;76(8):1081-1092.
https://hdl.handle.net/21.15107/rcub_technorep_1800 .

Dimitrijević, Aleksandra, Veličković, Dušan, Bezbradica, Dejan, Bihelović, Filip, Jankov, Ratko, Milosavić, Nenad, "Production of lipase from Pseudozyma aphidis and determination of the activity and stability of the crude lipase preparation in polar organic solvents" in Journal of the Serbian Chemical Society, 76, no. 8 (2011):1081-1092,
https://hdl.handle.net/21.15107/rcub_technorep_1800 .

TY  - JOUR
AU  - Žuža, Milena
AU  - Milosavić, Nenad
AU  - Knežević-Jugović, Zorica
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1810
AB  - Penicillin acylase (PAC) is an important industrial enzyme for the production of many β-lactam antibiotics. It is capable of catalyzing the hydrolysis of penicillin G (Pen G) to generate phenylacetic acid (PAA) and 6-aminopenicillanic acid (6-APA). In this paper, in order to prevent enzyme inactivation, an attempt of coupling enzyme modification and immobilization is presented. Chemical modification was promoted to introduce carbohydrate moiety into the PAC molecule, capable of being covalently linked to an amino support. This seems to provide a possibility to couple the enzyme without risking a reaction at the active site which might cause a loss of activity. PAC molecules were modified by cross-linking with polyaldehyde derivatives of alginate in order to add them new and useful functions. Immobilization of alginate-PAC on Sepabeads EC-HA was used as a model system in order to demonstrate the potential of this strategy. Optimal conditions for covalent immobilization of alginate-PAC from Escherichia coli on support Sepabeads EC-HA were investigated. The immobilized enzyme was then characterized by evaluating the potential effects of immobilization on its thermal stability, temperature and pH profile in comparison with native non-modified PAC and modified non-immobilized PAC. The maximum amount of the alginate-PAC coupled on the dry support of 99 mg/g was satisfactory. Deactivation rate constants at 50°C for free PAC, alginate-PAC and alginate-PAC immobilized on Sepabeads EC-HA were 2.32, 50.65 and 1.68 h-1, respectively. Alginate-PAC and alginate-PAC immobilized on Sepabeads EC-HA had the same pH and temperature optimum as the native non-modified PAC.
AB  - U ovom radu započeto je sistematsko ispitivanje imobilizacije enzima modifikovanih derivatima alginata. Penicilin-acilaza (PAC) modifikovana je polialdehidnim derivatom alginata i zatim imobilisana na Sepabeads EC-HA nosač. Ispitani su optimalni uslovi za kovalentnu imobilizaciju modifikovane PAC i imobilisani enzim je okarakterisan u pogledu efekata imobilizacije na njegovu termalnu stabilnost, pH i temperaturni profil. Dodatno, imobilisani enzim je po pitanju ovih parametara upoređen kako sa nativnom tako i sa modifikovanom (alginat-PAC) formom enzima. Konstante brzine dezaktivacije za PAC, alginat-PAC i modifikovan enzim imobilisan na Sepabeads EC-HA (alginat-PAC-Sepabeads EC-HA) iznosile su redom 2,03, 36,48 i 1,23 h-1 na 40°C, odnosno 2,32, 50,65 i 1,68 h-1 na 50°C. Pokazano je da alginat-PAC i alginat-PAC-Sepabeads EC-HA imaju isti pH i temperaturni optimum kao i nativna PAC.
PB  - Association of Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Immobilization of alginate-PAC on sepabeads EC-HA support
T1  - Imobilizacija penicilin-acilaze modifikovane derivatom alginata na sepabeads EC-HA nosač
EP  - 437
IS  - 4
SP  - 431
VL  - 65
DO  - 10.2298/HEMIND110318041Z
ER  - 

@article{
author = "Žuža, Milena and Milosavić, Nenad and Knežević-Jugović, Zorica",
year = "2011",
abstract = "Penicillin acylase (PAC) is an important industrial enzyme for the production of many β-lactam antibiotics. It is capable of catalyzing the hydrolysis of penicillin G (Pen G) to generate phenylacetic acid (PAA) and 6-aminopenicillanic acid (6-APA). In this paper, in order to prevent enzyme inactivation, an attempt of coupling enzyme modification and immobilization is presented. Chemical modification was promoted to introduce carbohydrate moiety into the PAC molecule, capable of being covalently linked to an amino support. This seems to provide a possibility to couple the enzyme without risking a reaction at the active site which might cause a loss of activity. PAC molecules were modified by cross-linking with polyaldehyde derivatives of alginate in order to add them new and useful functions. Immobilization of alginate-PAC on Sepabeads EC-HA was used as a model system in order to demonstrate the potential of this strategy. Optimal conditions for covalent immobilization of alginate-PAC from Escherichia coli on support Sepabeads EC-HA were investigated. The immobilized enzyme was then characterized by evaluating the potential effects of immobilization on its thermal stability, temperature and pH profile in comparison with native non-modified PAC and modified non-immobilized PAC. The maximum amount of the alginate-PAC coupled on the dry support of 99 mg/g was satisfactory. Deactivation rate constants at 50°C for free PAC, alginate-PAC and alginate-PAC immobilized on Sepabeads EC-HA were 2.32, 50.65 and 1.68 h-1, respectively. Alginate-PAC and alginate-PAC immobilized on Sepabeads EC-HA had the same pH and temperature optimum as the native non-modified PAC., U ovom radu započeto je sistematsko ispitivanje imobilizacije enzima modifikovanih derivatima alginata. Penicilin-acilaza (PAC) modifikovana je polialdehidnim derivatom alginata i zatim imobilisana na Sepabeads EC-HA nosač. Ispitani su optimalni uslovi za kovalentnu imobilizaciju modifikovane PAC i imobilisani enzim je okarakterisan u pogledu efekata imobilizacije na njegovu termalnu stabilnost, pH i temperaturni profil. Dodatno, imobilisani enzim je po pitanju ovih parametara upoređen kako sa nativnom tako i sa modifikovanom (alginat-PAC) formom enzima. Konstante brzine dezaktivacije za PAC, alginat-PAC i modifikovan enzim imobilisan na Sepabeads EC-HA (alginat-PAC-Sepabeads EC-HA) iznosile su redom 2,03, 36,48 i 1,23 h-1 na 40°C, odnosno 2,32, 50,65 i 1,68 h-1 na 50°C. Pokazano je da alginat-PAC i alginat-PAC-Sepabeads EC-HA imaju isti pH i temperaturni optimum kao i nativna PAC.",
publisher = "Association of Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Immobilization of alginate-PAC on sepabeads EC-HA support, Imobilizacija penicilin-acilaze modifikovane derivatom alginata na sepabeads EC-HA nosač",
pages = "437-431",
number = "4",
volume = "65",
doi = "10.2298/HEMIND110318041Z"
}

Žuža, M., Milosavić, N.,& Knežević-Jugović, Z.. (2011). Immobilization of alginate-PAC on sepabeads EC-HA support. in Hemijska industrija
Association of Chemical Engineers of Serbia., 65(4), 431-437.
https://doi.org/10.2298/HEMIND110318041Z

Žuža M, Milosavić N, Knežević-Jugović Z. Immobilization of alginate-PAC on sepabeads EC-HA support. in Hemijska industrija. 2011;65(4):431-437.
doi:10.2298/HEMIND110318041Z .

Žuža, Milena, Milosavić, Nenad, Knežević-Jugović, Zorica, "Immobilization of alginate-PAC on sepabeads EC-HA support" in Hemijska industrija, 65, no. 4 (2011):431-437,
https://doi.org/10.2298/HEMIND110318041Z . .

TY  - JOUR
AU  - Grbavčić, Sanja
AU  - Bezbradica, Dejan
AU  - Izrael-Zivković, Lidija
AU  - Avramović, Nataša
AU  - Milosavić, Nenad
AU  - Karadžić, Ivanka
AU  - Knežević-Jugović, Zorica
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1895
AB  - An indigenous Pseudomonas aeruginosa strain has been studied for lipase and protease activities for their potential application in detergents. Produced enzymes were investigated in order to assess their compatibility with several surfactants, oxidizing agents and commercial detergents. The crude lipase appeared to retain high activity and stability in the presence of several surfactants and oxidizing agents and it was insusceptible to proteolysis. Lutensol (R) XP80 and Triton (R) X-100 strongly activated the lipase for a long period (up to 40 and 30% against the control after 1 h) while the protease activity was enhanced by the addition of Triton (R) WR1339 and Tween (R) 80. The washing performance of the investigated surfactants was significantly improved with the addition of the crude enzyme preparation. Studies were further undertaken to improve enzymes production. The optimization of fermentation conditions led to an 8-fold increase of lipase production, while the production of protease was enhanced by 60%.
PB  - Elsevier Sci Ltd, Oxford
T2  - Bioresource Technology
T1  - Production of lipase and protease from an indigenous Pseudomonas aeruginosa strain and their evaluation as detergent additives: Compatibility study with detergent ingredients and washing performance
EP  - 11233
IS  - 24
SP  - 11226
VL  - 102
DO  - 10.1016/j.biortech.2011.09.076
ER  - 

@article{
author = "Grbavčić, Sanja and Bezbradica, Dejan and Izrael-Zivković, Lidija and Avramović, Nataša and Milosavić, Nenad and Karadžić, Ivanka and Knežević-Jugović, Zorica",
year = "2011",
abstract = "An indigenous Pseudomonas aeruginosa strain has been studied for lipase and protease activities for their potential application in detergents. Produced enzymes were investigated in order to assess their compatibility with several surfactants, oxidizing agents and commercial detergents. The crude lipase appeared to retain high activity and stability in the presence of several surfactants and oxidizing agents and it was insusceptible to proteolysis. Lutensol (R) XP80 and Triton (R) X-100 strongly activated the lipase for a long period (up to 40 and 30% against the control after 1 h) while the protease activity was enhanced by the addition of Triton (R) WR1339 and Tween (R) 80. The washing performance of the investigated surfactants was significantly improved with the addition of the crude enzyme preparation. Studies were further undertaken to improve enzymes production. The optimization of fermentation conditions led to an 8-fold increase of lipase production, while the production of protease was enhanced by 60%.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Bioresource Technology",
title = "Production of lipase and protease from an indigenous Pseudomonas aeruginosa strain and their evaluation as detergent additives: Compatibility study with detergent ingredients and washing performance",
pages = "11233-11226",
number = "24",
volume = "102",
doi = "10.1016/j.biortech.2011.09.076"
}

Grbavčić, S., Bezbradica, D., Izrael-Zivković, L., Avramović, N., Milosavić, N., Karadžić, I.,& Knežević-Jugović, Z.. (2011). Production of lipase and protease from an indigenous Pseudomonas aeruginosa strain and their evaluation as detergent additives: Compatibility study with detergent ingredients and washing performance. in Bioresource Technology
Elsevier Sci Ltd, Oxford., 102(24), 11226-11233.
https://doi.org/10.1016/j.biortech.2011.09.076

Grbavčić S, Bezbradica D, Izrael-Zivković L, Avramović N, Milosavić N, Karadžić I, Knežević-Jugović Z. Production of lipase and protease from an indigenous Pseudomonas aeruginosa strain and their evaluation as detergent additives: Compatibility study with detergent ingredients and washing performance. in Bioresource Technology. 2011;102(24):11226-11233.
doi:10.1016/j.biortech.2011.09.076 .

Grbavčić, Sanja, Bezbradica, Dejan, Izrael-Zivković, Lidija, Avramović, Nataša, Milosavić, Nenad, Karadžić, Ivanka, Knežević-Jugović, Zorica, "Production of lipase and protease from an indigenous Pseudomonas aeruginosa strain and their evaluation as detergent additives: Compatibility study with detergent ingredients and washing performance" in Bioresource Technology, 102, no. 24 (2011):11226-11233,
https://doi.org/10.1016/j.biortech.2011.09.076 . .

TY  - JOUR
AU  - Veličković, Dušan
AU  - Dimitrijević, Aleksandra
AU  - Bihelović, Filip
AU  - Bezbradica, Dejan
AU  - Jankov, Ratko
AU  - Milosavić, Nenad
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1891
AB  - In this report, alpha-isosalicin, a potent anticoagulant and skin whitening agent, was synthesized by a highly efficient chemoselective and diastereoselective reaction, catalyzed by maltase from bakers' yeast (Saccharomyces cerevisiae). The highest yield of this one-step transglucosylation reaction was achieved with 50 mM of salicyl alcohol as a glucose acceptor. The key reaction factors were optimized using response surface methodology (RSM) with an enzyme concentration of 10 U/mL. The optimum temperature of the reaction was determined as 36.5 degrees C, the optimal maltose concentration was 40% (w/v), the optimal pH was 6.5, and the optimal reaction time was 16 h. Under these conditions 75% of alpha-isosalicin was obtained, with a yield of 10 g/L, and no by product formation was observed.
PB  - Elsevier Sci Ltd, Oxford
T2  - Process Biochemistry
T1  - A highly efficient diastereoselective synthesis of alpha-isosalicin by maltase from Saccharomyces cerevisiae
EP  - 1702
IS  - 8
SP  - 1698
VL  - 46
DO  - 10.1016/j.procbio.2011.05.007
ER  - 

@article{
author = "Veličković, Dušan and Dimitrijević, Aleksandra and Bihelović, Filip and Bezbradica, Dejan and Jankov, Ratko and Milosavić, Nenad",
year = "2011",
abstract = "In this report, alpha-isosalicin, a potent anticoagulant and skin whitening agent, was synthesized by a highly efficient chemoselective and diastereoselective reaction, catalyzed by maltase from bakers' yeast (Saccharomyces cerevisiae). The highest yield of this one-step transglucosylation reaction was achieved with 50 mM of salicyl alcohol as a glucose acceptor. The key reaction factors were optimized using response surface methodology (RSM) with an enzyme concentration of 10 U/mL. The optimum temperature of the reaction was determined as 36.5 degrees C, the optimal maltose concentration was 40% (w/v), the optimal pH was 6.5, and the optimal reaction time was 16 h. Under these conditions 75% of alpha-isosalicin was obtained, with a yield of 10 g/L, and no by product formation was observed.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Process Biochemistry",
title = "A highly efficient diastereoselective synthesis of alpha-isosalicin by maltase from Saccharomyces cerevisiae",
pages = "1702-1698",
number = "8",
volume = "46",
doi = "10.1016/j.procbio.2011.05.007"
}

Veličković, D., Dimitrijević, A., Bihelović, F., Bezbradica, D., Jankov, R.,& Milosavić, N.. (2011). A highly efficient diastereoselective synthesis of alpha-isosalicin by maltase from Saccharomyces cerevisiae. in Process Biochemistry
Elsevier Sci Ltd, Oxford., 46(8), 1698-1702.
https://doi.org/10.1016/j.procbio.2011.05.007

Veličković D, Dimitrijević A, Bihelović F, Bezbradica D, Jankov R, Milosavić N. A highly efficient diastereoselective synthesis of alpha-isosalicin by maltase from Saccharomyces cerevisiae. in Process Biochemistry. 2011;46(8):1698-1702.
doi:10.1016/j.procbio.2011.05.007 .

Veličković, Dušan, Dimitrijević, Aleksandra, Bihelović, Filip, Bezbradica, Dejan, Jankov, Ratko, Milosavić, Nenad, "A highly efficient diastereoselective synthesis of alpha-isosalicin by maltase from Saccharomyces cerevisiae" in Process Biochemistry, 46, no. 8 (2011):1698-1702,
https://doi.org/10.1016/j.procbio.2011.05.007 . .