TY  - JOUR
AU  - Veličković, Dušan
AU  - Zhang, Guanshi
AU  - Bezbradica, Dejan
AU  - Bhattacharjee, Arunima
AU  - Pasa-Tolić, Ljiljana
AU  - Sharma, Kumar
AU  - Alexandrov, Theodore
AU  - Anderton, Christopher R.
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4489
AB  - Automated spraying devices have become ubiquitous in laboratories employing matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), in part because they permit control of a number of matrix application parameters that can easily be reproduced for intra- and interlaboratory studies. Determining the optimal parameters for MALDI matrix application, such as temperature, flow rate, spraying velocity, number of spraying cycles, and solvent composition for matrix application, is critical for obtaining high-quality MALDI-MSI data. However, there are no established approaches for optimizing these multiple parameters simultaneously. Instead optimization is performed iteratively (i.e., one parameter at a time), which is time-consuming and can lead to overall nonoptimal settings. In this report, we demonstrate the use a novel experimental design and the response surface methodology to optimize five parameters of MALDI matrix application using a robotic sprayer. Thirty-two combinations of MALDI matrix spraying conditions were tested, which allowed us to elucidate relationships between each of the application parameters as determined by MALDI-MS (specifically, using a 15 T Fourier transform ion cyclotron resonance mass spectrometer). As such, we were able to determine the optimal automated spraying parameters that minimized signal delocalization and enabled high MALDI sensitivity. We envision this optimization strategy can be utilized for other matrix application approaches and MALDI-MSI analyses of other molecular classes and tissue types.
PB  - Amer Chemical Soc, Washington
T2  - Journal of the American Society for Mass Spectrometry
T1  - Response Surface Methodology As a New Approach for Finding Optimal MALDI Matrix Spraying Parameters for Mass Spectrometry Imaging
EP  - 516
IS  - 3
SP  - 508
VL  - 31
DO  - 10.1021/jasms.9b00074
ER  - 

@article{
author = "Veličković, Dušan and Zhang, Guanshi and Bezbradica, Dejan and Bhattacharjee, Arunima and Pasa-Tolić, Ljiljana and Sharma, Kumar and Alexandrov, Theodore and Anderton, Christopher R.",
year = "2020",
abstract = "Automated spraying devices have become ubiquitous in laboratories employing matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), in part because they permit control of a number of matrix application parameters that can easily be reproduced for intra- and interlaboratory studies. Determining the optimal parameters for MALDI matrix application, such as temperature, flow rate, spraying velocity, number of spraying cycles, and solvent composition for matrix application, is critical for obtaining high-quality MALDI-MSI data. However, there are no established approaches for optimizing these multiple parameters simultaneously. Instead optimization is performed iteratively (i.e., one parameter at a time), which is time-consuming and can lead to overall nonoptimal settings. In this report, we demonstrate the use a novel experimental design and the response surface methodology to optimize five parameters of MALDI matrix application using a robotic sprayer. Thirty-two combinations of MALDI matrix spraying conditions were tested, which allowed us to elucidate relationships between each of the application parameters as determined by MALDI-MS (specifically, using a 15 T Fourier transform ion cyclotron resonance mass spectrometer). As such, we were able to determine the optimal automated spraying parameters that minimized signal delocalization and enabled high MALDI sensitivity. We envision this optimization strategy can be utilized for other matrix application approaches and MALDI-MSI analyses of other molecular classes and tissue types.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of the American Society for Mass Spectrometry",
title = "Response Surface Methodology As a New Approach for Finding Optimal MALDI Matrix Spraying Parameters for Mass Spectrometry Imaging",
pages = "516-508",
number = "3",
volume = "31",
doi = "10.1021/jasms.9b00074"
}

Veličković, D., Zhang, G., Bezbradica, D., Bhattacharjee, A., Pasa-Tolić, L., Sharma, K., Alexandrov, T.,& Anderton, C. R.. (2020). Response Surface Methodology As a New Approach for Finding Optimal MALDI Matrix Spraying Parameters for Mass Spectrometry Imaging. in Journal of the American Society for Mass Spectrometry
Amer Chemical Soc, Washington., 31(3), 508-516.
https://doi.org/10.1021/jasms.9b00074

Veličković D, Zhang G, Bezbradica D, Bhattacharjee A, Pasa-Tolić L, Sharma K, Alexandrov T, Anderton CR. Response Surface Methodology As a New Approach for Finding Optimal MALDI Matrix Spraying Parameters for Mass Spectrometry Imaging. in Journal of the American Society for Mass Spectrometry. 2020;31(3):508-516.
doi:10.1021/jasms.9b00074 .

Veličković, Dušan, Zhang, Guanshi, Bezbradica, Dejan, Bhattacharjee, Arunima, Pasa-Tolić, Ljiljana, Sharma, Kumar, Alexandrov, Theodore, Anderton, Christopher R., "Response Surface Methodology As a New Approach for Finding Optimal MALDI Matrix Spraying Parameters for Mass Spectrometry Imaging" in Journal of the American Society for Mass Spectrometry, 31, no. 3 (2020):508-516,
https://doi.org/10.1021/jasms.9b00074 . .

TY  - JOUR
AU  - Carević, Milica
AU  - Vukašinović-Sekulić, Maja
AU  - Ćorović, Marija
AU  - Rogniaux, Helene
AU  - Ropartz, David
AU  - Veličković, Dušan
AU  - Bezbradica, Dejan
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3934
AB  - beta-Galactosidase is an important industrial enzyme that catalyzes reaction of lactose hydrolysis and recently more interesting reaction of transgalactosylation, yielding a highly valuable group of prebiotic compounds named galacto-oligosaccharides (GOS). In this paper, parameters for achieving high yields of tailor-made GOS using crude beta-galactosidase obtained from Lactobacillus acidophilus ATCC 4356, probiotic bacteria regarded as safe for human consumption, were optimized. At the same time, detailed structural elucidation of obtained GOS was conducted, and it was concluded that beta-galactosidase from L acidophilus shows a particular specificity towards the formation of beta-(1 - gt  6) glycosidic bonds. In order to develop more stable and economically cost-effective preparation, crude enzyme was successfully immobilized on a methacrylic polymer carrier Lifetech ECR8409, leading to its simultaneous 2-fold purification. This immobilized preparation showed unchanged specificity towards the transgalactosylation reaction, thus yielding 86 WI GOS under the previously optimized conditions (lactose concentration 400 g/l in 0.1 M sodium phosphate buffer, pH 6.8 and temperature 50 degrees C).
PB  - Soc Bioscience Bioengineering Japan, Osaka
T2  - Journal of Bioscience and Bioengineering
T1  - Evaluation of beta-galactosidase from Lactobacillus acidophilus as biocatalyst for galacto-oligosaccharides synthesis: Product structural characterization and enzyme immobilization
EP  - 704
IS  - 6
SP  - 697
VL  - 126
DO  - 10.1016/j.jbiosc.2018.06.003
ER  - 

@article{
author = "Carević, Milica and Vukašinović-Sekulić, Maja and Ćorović, Marija and Rogniaux, Helene and Ropartz, David and Veličković, Dušan and Bezbradica, Dejan",
year = "2018",
abstract = "beta-Galactosidase is an important industrial enzyme that catalyzes reaction of lactose hydrolysis and recently more interesting reaction of transgalactosylation, yielding a highly valuable group of prebiotic compounds named galacto-oligosaccharides (GOS). In this paper, parameters for achieving high yields of tailor-made GOS using crude beta-galactosidase obtained from Lactobacillus acidophilus ATCC 4356, probiotic bacteria regarded as safe for human consumption, were optimized. At the same time, detailed structural elucidation of obtained GOS was conducted, and it was concluded that beta-galactosidase from L acidophilus shows a particular specificity towards the formation of beta-(1 - gt  6) glycosidic bonds. In order to develop more stable and economically cost-effective preparation, crude enzyme was successfully immobilized on a methacrylic polymer carrier Lifetech ECR8409, leading to its simultaneous 2-fold purification. This immobilized preparation showed unchanged specificity towards the transgalactosylation reaction, thus yielding 86 WI GOS under the previously optimized conditions (lactose concentration 400 g/l in 0.1 M sodium phosphate buffer, pH 6.8 and temperature 50 degrees C).",
publisher = "Soc Bioscience Bioengineering Japan, Osaka",
journal = "Journal of Bioscience and Bioengineering",
title = "Evaluation of beta-galactosidase from Lactobacillus acidophilus as biocatalyst for galacto-oligosaccharides synthesis: Product structural characterization and enzyme immobilization",
pages = "704-697",
number = "6",
volume = "126",
doi = "10.1016/j.jbiosc.2018.06.003"
}

Carević, M., Vukašinović-Sekulić, M., Ćorović, M., Rogniaux, H., Ropartz, D., Veličković, D.,& Bezbradica, D.. (2018). Evaluation of beta-galactosidase from Lactobacillus acidophilus as biocatalyst for galacto-oligosaccharides synthesis: Product structural characterization and enzyme immobilization. in Journal of Bioscience and Bioengineering
Soc Bioscience Bioengineering Japan, Osaka., 126(6), 697-704.
https://doi.org/10.1016/j.jbiosc.2018.06.003

Carević M, Vukašinović-Sekulić M, Ćorović M, Rogniaux H, Ropartz D, Veličković D, Bezbradica D. Evaluation of beta-galactosidase from Lactobacillus acidophilus as biocatalyst for galacto-oligosaccharides synthesis: Product structural characterization and enzyme immobilization. in Journal of Bioscience and Bioengineering. 2018;126(6):697-704.
doi:10.1016/j.jbiosc.2018.06.003 .

Carević, Milica, Vukašinović-Sekulić, Maja, Ćorović, Marija, Rogniaux, Helene, Ropartz, David, Veličković, Dušan, Bezbradica, Dejan, "Evaluation of beta-galactosidase from Lactobacillus acidophilus as biocatalyst for galacto-oligosaccharides synthesis: Product structural characterization and enzyme immobilization" in Journal of Bioscience and Bioengineering, 126, no. 6 (2018):697-704,
https://doi.org/10.1016/j.jbiosc.2018.06.003 . .

TY  - JOUR
AU  - Milivojević, Ana
AU  - Ćorović, Marija
AU  - Simović, Milica
AU  - Banjanac, Katarina
AU  - Vujisić, Ljubodrag V.
AU  - Veličković, Dušan
AU  - Bezbradica, Dejan
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3593
AB  - Solubility and stability of flavonoid glycosides, valuable natural constituents of cosmetics and pharmaceuticals, could be improved by lipase-catalyzed acylation. Focus of this study was on development of eco-friendly process for the production of flavonoid acetates. By using phloridzin as model compound and triacetin as acetyl donor and solvent, 100% conversion and high productivity (23.32 gl(-1) day(-1)) were accomplished. Complete conversions of two other glycosylated flavonoids, naringin and esculin, in solvent-free system were achieved, as well. Comprehensive kinetic mechanism based on two con-secutive mono-substrate reactions was established where first one represents formation of flavonoid monoacetate and within second reaction diacetate is being produced from monoacetate. Both steps were regarded as reversible Michaelis-Menten reactions without inhibition. Apparent kinetic parameters for two consecutive reactions (V-m constants for substrates and products and Km constants for forward and reverse reactions) were estimated for three examined acetyl acceptors and excellent fitting of experimental data (R-2 gt 0.97) was achieved. Obtained results showed that derived kinetic model could be applicable for solvent-free esterifications of different flavonoid glycosides. It was valid for entire transesterification course (72 h of reaction) which, combined with complete conversions and green character of synthesis, represents firm basis for further process development.
PB  - Elsevier Science Bv, Amsterdam
T2  - Biochemical Engineering Journal
T1  - Highly efficient enzymatic acetylation of flavonoids: Development of solvent-free process and kinetic evaluation
EP  - 115
SP  - 106
VL  - 128
DO  - 10.1016/j.bej.2017.09.018
ER  - 

@article{
author = "Milivojević, Ana and Ćorović, Marija and Simović, Milica and Banjanac, Katarina and Vujisić, Ljubodrag V. and Veličković, Dušan and Bezbradica, Dejan",
year = "2017",
abstract = "Solubility and stability of flavonoid glycosides, valuable natural constituents of cosmetics and pharmaceuticals, could be improved by lipase-catalyzed acylation. Focus of this study was on development of eco-friendly process for the production of flavonoid acetates. By using phloridzin as model compound and triacetin as acetyl donor and solvent, 100% conversion and high productivity (23.32 gl(-1) day(-1)) were accomplished. Complete conversions of two other glycosylated flavonoids, naringin and esculin, in solvent-free system were achieved, as well. Comprehensive kinetic mechanism based on two con-secutive mono-substrate reactions was established where first one represents formation of flavonoid monoacetate and within second reaction diacetate is being produced from monoacetate. Both steps were regarded as reversible Michaelis-Menten reactions without inhibition. Apparent kinetic parameters for two consecutive reactions (V-m constants for substrates and products and Km constants for forward and reverse reactions) were estimated for three examined acetyl acceptors and excellent fitting of experimental data (R-2 gt 0.97) was achieved. Obtained results showed that derived kinetic model could be applicable for solvent-free esterifications of different flavonoid glycosides. It was valid for entire transesterification course (72 h of reaction) which, combined with complete conversions and green character of synthesis, represents firm basis for further process development.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Biochemical Engineering Journal",
title = "Highly efficient enzymatic acetylation of flavonoids: Development of solvent-free process and kinetic evaluation",
pages = "115-106",
volume = "128",
doi = "10.1016/j.bej.2017.09.018"
}

Milivojević, A., Ćorović, M., Simović, M., Banjanac, K., Vujisić, L. V., Veličković, D.,& Bezbradica, D.. (2017). Highly efficient enzymatic acetylation of flavonoids: Development of solvent-free process and kinetic evaluation. in Biochemical Engineering Journal
Elsevier Science Bv, Amsterdam., 128, 106-115.
https://doi.org/10.1016/j.bej.2017.09.018

Milivojević A, Ćorović M, Simović M, Banjanac K, Vujisić LV, Veličković D, Bezbradica D. Highly efficient enzymatic acetylation of flavonoids: Development of solvent-free process and kinetic evaluation. in Biochemical Engineering Journal. 2017;128:106-115.
doi:10.1016/j.bej.2017.09.018 .

Milivojević, Ana, Ćorović, Marija, Simović, Milica, Banjanac, Katarina, Vujisić, Ljubodrag V., Veličković, Dušan, Bezbradica, Dejan, "Highly efficient enzymatic acetylation of flavonoids: Development of solvent-free process and kinetic evaluation" in Biochemical Engineering Journal, 128 (2017):106-115,
https://doi.org/10.1016/j.bej.2017.09.018 . .

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  - Simović, Milica
AU  - Ćorović, Marija
AU  - Mihailović, Mladen
AU  - Banjanac, Katarina
AU  - Milivojević, Ana
AU  - Veličković, Dušan
AU  - Bezbradica, Dejan
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3374
AB  - The goal of this study was to establish an efficient immobilisation protocol for beta-galactosidase from Aspergillus oryzae onto the polystyrenic macroporous resin Purolite (R) A-109 for better utilisation of its transglactosylation activity and application in galacto-oligosaccharide (GOS) synthesis. This was achieved by improving simple ionic adsorption by carboxyl group activation on the enzyme surface with carbodiimide, enabling covalent immobilisation. This yielded significantly increased operational stability, assayed as GOS synthesis, in a batch reactor, and even more prominently, in a fluidised bed reactor (73% activity retained after 10 cycles). The immobilised enzyme showed two very beneficial advantages over the free enzyme for future applications: higher affinity towards catalysing transgalactosylation than towards hydrolysis and shift of pH optimum towards more acidic conditions. GOS synthesis performed under the optimum conditions obtained (400 g L-1 lactose, pH 4.5, 50 degrees C) yielded 87 g L-1 and 100 g L-1 for batch and fluidised bed reactors, respectively.
PB  - Elsevier Sci Ltd, Oxford
T2  - International Dairy Journal
T1  - Galacto-oligosaccharide synthesis using chemically modified beta-galactosidase from Aspergillus oryzae immobilised onto macroporous amino resin
EP  - 57
SP  - 50
VL  - 54
DO  - 10.1016/j.idairyj.2015.10.002
ER  - 

@article{
author = "Simović, Milica and Ćorović, Marija and Mihailović, Mladen and Banjanac, Katarina and Milivojević, Ana and Veličković, Dušan and Bezbradica, Dejan",
year = "2016",
abstract = "The goal of this study was to establish an efficient immobilisation protocol for beta-galactosidase from Aspergillus oryzae onto the polystyrenic macroporous resin Purolite (R) A-109 for better utilisation of its transglactosylation activity and application in galacto-oligosaccharide (GOS) synthesis. This was achieved by improving simple ionic adsorption by carboxyl group activation on the enzyme surface with carbodiimide, enabling covalent immobilisation. This yielded significantly increased operational stability, assayed as GOS synthesis, in a batch reactor, and even more prominently, in a fluidised bed reactor (73% activity retained after 10 cycles). The immobilised enzyme showed two very beneficial advantages over the free enzyme for future applications: higher affinity towards catalysing transgalactosylation than towards hydrolysis and shift of pH optimum towards more acidic conditions. GOS synthesis performed under the optimum conditions obtained (400 g L-1 lactose, pH 4.5, 50 degrees C) yielded 87 g L-1 and 100 g L-1 for batch and fluidised bed reactors, respectively.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "International Dairy Journal",
title = "Galacto-oligosaccharide synthesis using chemically modified beta-galactosidase from Aspergillus oryzae immobilised onto macroporous amino resin",
pages = "57-50",
volume = "54",
doi = "10.1016/j.idairyj.2015.10.002"
}

Simović, M., Ćorović, M., Mihailović, M., Banjanac, K., Milivojević, A., Veličković, D.,& Bezbradica, D.. (2016). Galacto-oligosaccharide synthesis using chemically modified beta-galactosidase from Aspergillus oryzae immobilised onto macroporous amino resin. in International Dairy Journal
Elsevier Sci Ltd, Oxford., 54, 50-57.
https://doi.org/10.1016/j.idairyj.2015.10.002

Simović M, Ćorović M, Mihailović M, Banjanac K, Milivojević A, Veličković D, Bezbradica D. Galacto-oligosaccharide synthesis using chemically modified beta-galactosidase from Aspergillus oryzae immobilised onto macroporous amino resin. in International Dairy Journal. 2016;54:50-57.
doi:10.1016/j.idairyj.2015.10.002 .

Simović, Milica, Ćorović, Marija, Mihailović, Mladen, Banjanac, Katarina, Milivojević, Ana, Veličković, Dušan, Bezbradica, Dejan, "Galacto-oligosaccharide synthesis using chemically modified beta-galactosidase from Aspergillus oryzae immobilised onto macroporous amino resin" in International Dairy Journal, 54 (2016):50-57,
https://doi.org/10.1016/j.idairyj.2015.10.002 . .

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  - Simović, Milica
AU  - Bezbradica, Dejan
AU  - Banjanac, Katarina
AU  - Milivojević, Ana
AU  - Fanuel, Mathieu
AU  - Rogniaux, Helene
AU  - Ropartz, David
AU  - Veličković, Dušan
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3258
AB  - Galacto-oligosaccharides (GOS) represent a diverse group of well-characterized prebiotic ingredients derived from lactose in a reaction catalyzed with beta-galactosidases. Enzymatic transgalactosylation results in a mixture of compounds of various degrees of polymerization and types of linkages. Because structure plays an important role in terms of prebiotic activity, it is of crucial importance to provide an insight into the mechanism of transgalactosylation reaction and occurrence of different types of beta-linkages during GOS synthesis. Our study proved that a novel one-step method, based on ion-mobility spectrometry tandem mass spectrometry (IMS-MS/MS), enables complete elucidation of GOS structure. It has been shown that) beta-galactosidase from Aspergillus oryzae has the highest affinity toward formation of beta-(1 - gt  3) or beta-(1 - gt  6) linkages. Additionally, it was observed that the occurrence of different linkages varies during the reaction course, indicating that tailoring favorable GOS structures with improved prebiotic activity can be achieved by adequate control of enzymatic synthesis.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Agricultural and Food Chemistry
T1  - Structural Elucidation of Enzymatically Synthesized Galacto-oligosaccharides Using Ion-Mobility Spectrometry Tandem Mass Spectrometry
EP  - 3615
IS  - 18
SP  - 3609
VL  - 64
DO  - 10.1021/acs.jafc.6b01293
ER  - 

@article{
author = "Simović, Milica and Bezbradica, Dejan and Banjanac, Katarina and Milivojević, Ana and Fanuel, Mathieu and Rogniaux, Helene and Ropartz, David and Veličković, Dušan",
year = "2016",
abstract = "Galacto-oligosaccharides (GOS) represent a diverse group of well-characterized prebiotic ingredients derived from lactose in a reaction catalyzed with beta-galactosidases. Enzymatic transgalactosylation results in a mixture of compounds of various degrees of polymerization and types of linkages. Because structure plays an important role in terms of prebiotic activity, it is of crucial importance to provide an insight into the mechanism of transgalactosylation reaction and occurrence of different types of beta-linkages during GOS synthesis. Our study proved that a novel one-step method, based on ion-mobility spectrometry tandem mass spectrometry (IMS-MS/MS), enables complete elucidation of GOS structure. It has been shown that) beta-galactosidase from Aspergillus oryzae has the highest affinity toward formation of beta-(1 - gt  3) or beta-(1 - gt  6) linkages. Additionally, it was observed that the occurrence of different linkages varies during the reaction course, indicating that tailoring favorable GOS structures with improved prebiotic activity can be achieved by adequate control of enzymatic synthesis.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Agricultural and Food Chemistry",
title = "Structural Elucidation of Enzymatically Synthesized Galacto-oligosaccharides Using Ion-Mobility Spectrometry Tandem Mass Spectrometry",
pages = "3615-3609",
number = "18",
volume = "64",
doi = "10.1021/acs.jafc.6b01293"
}

Simović, M., Bezbradica, D., Banjanac, K., Milivojević, A., Fanuel, M., Rogniaux, H., Ropartz, D.,& Veličković, D.. (2016). Structural Elucidation of Enzymatically Synthesized Galacto-oligosaccharides Using Ion-Mobility Spectrometry Tandem Mass Spectrometry. in Journal of Agricultural and Food Chemistry
Amer Chemical Soc, Washington., 64(18), 3609-3615.
https://doi.org/10.1021/acs.jafc.6b01293

Simović M, Bezbradica D, Banjanac K, Milivojević A, Fanuel M, Rogniaux H, Ropartz D, Veličković D. Structural Elucidation of Enzymatically Synthesized Galacto-oligosaccharides Using Ion-Mobility Spectrometry Tandem Mass Spectrometry. in Journal of Agricultural and Food Chemistry. 2016;64(18):3609-3615.
doi:10.1021/acs.jafc.6b01293 .

Simović, Milica, Bezbradica, Dejan, Banjanac, Katarina, Milivojević, Ana, Fanuel, Mathieu, Rogniaux, Helene, Ropartz, David, Veličković, Dušan, "Structural Elucidation of Enzymatically Synthesized Galacto-oligosaccharides Using Ion-Mobility Spectrometry Tandem Mass Spectrometry" in Journal of Agricultural and Food Chemistry, 64, no. 18 (2016):3609-3615,
https://doi.org/10.1021/acs.jafc.6b01293 . .

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  - 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  - 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  - Prlainović, Nevena
AU  - Bezbradica, Dejan
AU  - Knežević-Jugović, Zorica
AU  - Veličković, Dušan
AU  - Mijin, Dušan
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2356
AB  - 3-Cyano-4-(ethoxymethyl)-6-methyl-2-pyridone, an important precursor in the synthesis of vitamin B6, is obtained in the addition reaction between 2-cyanoacetamide and 1-ethoxy-2,4-pentanedione catalyzed by lipase from Candida rugosa (triacylglycerol acylhydrolases, EC 3.1.1.3). This work shows new experimental data and mathematical modeling of the lipase-catalyzed synthesis of 3-cyano-4-(ethoxymethyl)-6-methyl-2-pyridone. Kinetic measurements were performed at 50 °C with an enzyme concentration of 1.2 % w/v. The experimental results were fitted with two kinetic models: the ordered bi-ter and ping-pong bi-ter model, and the initial rates of the reaction were found to correlate best with the ping-pong bi-ter mechanism with inhibition by 2-cyanoacetamide. The obtained specificity constants indicated that lipase from C. rugosa had a higher affinity towards 1-ethoxy-2,4-pentanedione compared to 2-cyanoacetamide.
AB  - 3-Cijano-4-(etoksimetil)-6-metil-2-piridon je veoma važan prekursor u sintezi vitamina B6. Dobija se u reakciji između molekula 2-cijanoacetamida i 1-etoksi-2,4-pentandiona katalizovanoj lipazom iz Candida rugosa (triacilglicerol-acil-hidrolaza, EC 3.1.1.3). Rezultati ovog rada predstavljaju set novih eksperimentalnih podataka brzine enzimske sinteze 3-cijano-4-(etoksimetil)-6-metil-2-piridona. Matematičkim modelovanjem ovih podataka dobijeni su podaci o kinetici ispitane reakcije. Kinetička merenja vršena su na temperaturi od 50 °C pri koncentraciji enzima od 1,2 % m/v. Dobijeni rezultati fitovani su sa dva različita matematička modela (ping-pong model sa inhibicijom 2-cijanoacetamidom i sekvencijalni model sa pravilnim redosledom vezivanja sa inhibicijom 2-cijanoacetamidom). Vrednosti koeficijenata linearnosti pokazuju da se početne brzine reakcije pri različitim početnim koncentracijama supstrata najbolje mogu opisati ping-pong bi-ter modelom pri čemu postoji inhibicija 2-cijanoacetamidom. U radu je dat i grafički prikaz ping-pong modela. Dobijene konstante specifičnosti ukazuju na to da lipaza iz C. rugosa ima veći afinitet prema 1-etoksi-2,4-pentandionu u poređenju sa 2-cijanoacetamidom.
PB  - Serbian Chemical Society, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - Enzymatic synthesis of a vitamin B6 precursor
T1  - Enzimska sinteza prekursora vitamina B6
EP  - 1501
IS  - 10
SP  - 1491
VL  - 78
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2356
ER  - 

@article{
author = "Prlainović, Nevena and Bezbradica, Dejan and Knežević-Jugović, Zorica and Veličković, Dušan and Mijin, Dušan",
year = "2013",
abstract = "3-Cyano-4-(ethoxymethyl)-6-methyl-2-pyridone, an important precursor in the synthesis of vitamin B6, is obtained in the addition reaction between 2-cyanoacetamide and 1-ethoxy-2,4-pentanedione catalyzed by lipase from Candida rugosa (triacylglycerol acylhydrolases, EC 3.1.1.3). This work shows new experimental data and mathematical modeling of the lipase-catalyzed synthesis of 3-cyano-4-(ethoxymethyl)-6-methyl-2-pyridone. Kinetic measurements were performed at 50 °C with an enzyme concentration of 1.2 % w/v. The experimental results were fitted with two kinetic models: the ordered bi-ter and ping-pong bi-ter model, and the initial rates of the reaction were found to correlate best with the ping-pong bi-ter mechanism with inhibition by 2-cyanoacetamide. The obtained specificity constants indicated that lipase from C. rugosa had a higher affinity towards 1-ethoxy-2,4-pentanedione compared to 2-cyanoacetamide., 3-Cijano-4-(etoksimetil)-6-metil-2-piridon je veoma važan prekursor u sintezi vitamina B6. Dobija se u reakciji između molekula 2-cijanoacetamida i 1-etoksi-2,4-pentandiona katalizovanoj lipazom iz Candida rugosa (triacilglicerol-acil-hidrolaza, EC 3.1.1.3). Rezultati ovog rada predstavljaju set novih eksperimentalnih podataka brzine enzimske sinteze 3-cijano-4-(etoksimetil)-6-metil-2-piridona. Matematičkim modelovanjem ovih podataka dobijeni su podaci o kinetici ispitane reakcije. Kinetička merenja vršena su na temperaturi od 50 °C pri koncentraciji enzima od 1,2 % m/v. Dobijeni rezultati fitovani su sa dva različita matematička modela (ping-pong model sa inhibicijom 2-cijanoacetamidom i sekvencijalni model sa pravilnim redosledom vezivanja sa inhibicijom 2-cijanoacetamidom). Vrednosti koeficijenata linearnosti pokazuju da se početne brzine reakcije pri različitim početnim koncentracijama supstrata najbolje mogu opisati ping-pong bi-ter modelom pri čemu postoji inhibicija 2-cijanoacetamidom. U radu je dat i grafički prikaz ping-pong modela. Dobijene konstante specifičnosti ukazuju na to da lipaza iz C. rugosa ima veći afinitet prema 1-etoksi-2,4-pentandionu u poređenju sa 2-cijanoacetamidom.",
publisher = "Serbian Chemical Society, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "Enzymatic synthesis of a vitamin B6 precursor, Enzimska sinteza prekursora vitamina B6",
pages = "1501-1491",
number = "10",
volume = "78",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2356"
}

Prlainović, N., Bezbradica, D., Knežević-Jugović, Z., Veličković, D.,& Mijin, D.. (2013). Enzymatic synthesis of a vitamin B6 precursor. in Journal of the Serbian Chemical Society
Serbian Chemical Society, Belgrade., 78(10), 1491-1501.
https://hdl.handle.net/21.15107/rcub_technorep_2356

Prlainović N, Bezbradica D, Knežević-Jugović Z, Veličković D, Mijin D. Enzymatic synthesis of a vitamin B6 precursor. in Journal of the Serbian Chemical Society. 2013;78(10):1491-1501.
https://hdl.handle.net/21.15107/rcub_technorep_2356 .

Prlainović, Nevena, Bezbradica, Dejan, Knežević-Jugović, Zorica, Veličković, Dušan, Mijin, Dušan, "Enzymatic synthesis of a vitamin B6 precursor" in Journal of the Serbian Chemical Society, 78, no. 10 (2013):1491-1501,
https://hdl.handle.net/21.15107/rcub_technorep_2356 .

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 .