TY  - JOUR
AU  - Milašinović, Nikola
AU  - Knežević-Jugović, Zorica
AU  - Jakovljević, Živana
AU  - Filipović, Jovanka
AU  - Kalagasidis Krušić, Melina
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2235
AB  - A commercial Candida rugosa lipase was immobilized into poly(N-isopropylacrylamide-co-itaconic acid) hydrogel under different pH immobilization conditions, characterized and evaluated for both hydrolytic activity in an aqueous medium and esterolytic activity in an organic medium. Although the apparent enzyme activity in the hydrolytic reaction was acceptable, the immobilized lipase appeared to be more suitable for application in ester synthesis in low aqueous system based on n-hexane. The esterification reaction parameters, such as temperature, biocatalyst amount, added water content and substrate concentration was evaluated and optimized by response surface analysis. An adequate statistical quadratic model was obtained, making it possible to predict ester yields from known values of the four main factors. Under optimized conditions, the yield of ester  gt 90% could be achieved after 48 h of reaction, corresponding to the volumetric activity of 4.75 mmol L-1 h(-1). The operational stability of the immobilized system in esterification reaction proved to be highly attractive with 15 consecutive 48 h uses with a residual activity of 67.4%, implying that the developed hydrogel and immobilized system could provide a promising solution for the flavor ester synthesis at the industrial scale.
PB  - Elsevier Science Sa, Lausanne
T2  - Chemical Engineering Journal
T1  - Synthesis of n-amyl isobutyrate catalyzed by Candida rugosa lipase immobilized into poly(N-isopropylacrylamide-co-itaconic acid) hydrogels
EP  - 623
SP  - 614
VL  - 181
DO  - 10.1016/j.cej.2011.11.115
ER  - 

@article{
author = "Milašinović, Nikola and Knežević-Jugović, Zorica and Jakovljević, Živana and Filipović, Jovanka and Kalagasidis Krušić, Melina",
year = "2012",
abstract = "A commercial Candida rugosa lipase was immobilized into poly(N-isopropylacrylamide-co-itaconic acid) hydrogel under different pH immobilization conditions, characterized and evaluated for both hydrolytic activity in an aqueous medium and esterolytic activity in an organic medium. Although the apparent enzyme activity in the hydrolytic reaction was acceptable, the immobilized lipase appeared to be more suitable for application in ester synthesis in low aqueous system based on n-hexane. The esterification reaction parameters, such as temperature, biocatalyst amount, added water content and substrate concentration was evaluated and optimized by response surface analysis. An adequate statistical quadratic model was obtained, making it possible to predict ester yields from known values of the four main factors. Under optimized conditions, the yield of ester  gt 90% could be achieved after 48 h of reaction, corresponding to the volumetric activity of 4.75 mmol L-1 h(-1). The operational stability of the immobilized system in esterification reaction proved to be highly attractive with 15 consecutive 48 h uses with a residual activity of 67.4%, implying that the developed hydrogel and immobilized system could provide a promising solution for the flavor ester synthesis at the industrial scale.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Chemical Engineering Journal",
title = "Synthesis of n-amyl isobutyrate catalyzed by Candida rugosa lipase immobilized into poly(N-isopropylacrylamide-co-itaconic acid) hydrogels",
pages = "623-614",
volume = "181",
doi = "10.1016/j.cej.2011.11.115"
}

Milašinović, N., Knežević-Jugović, Z., Jakovljević, Ž., Filipović, J.,& Kalagasidis Krušić, M.. (2012). Synthesis of n-amyl isobutyrate catalyzed by Candida rugosa lipase immobilized into poly(N-isopropylacrylamide-co-itaconic acid) hydrogels. in Chemical Engineering Journal
Elsevier Science Sa, Lausanne., 181, 614-623.
https://doi.org/10.1016/j.cej.2011.11.115

Milašinović N, Knežević-Jugović Z, Jakovljević Ž, Filipović J, Kalagasidis Krušić M. Synthesis of n-amyl isobutyrate catalyzed by Candida rugosa lipase immobilized into poly(N-isopropylacrylamide-co-itaconic acid) hydrogels. in Chemical Engineering Journal. 2012;181:614-623.
doi:10.1016/j.cej.2011.11.115 .

Milašinović, Nikola, Knežević-Jugović, Zorica, Jakovljević, Živana, Filipović, Jovanka, Kalagasidis Krušić, Melina, "Synthesis of n-amyl isobutyrate catalyzed by Candida rugosa lipase immobilized into poly(N-isopropylacrylamide-co-itaconic acid) hydrogels" in Chemical Engineering Journal, 181 (2012):614-623,
https://doi.org/10.1016/j.cej.2011.11.115 . .

TY  - JOUR
AU  - Knežević-Jugović, Zorica
AU  - Bezbradica, Dejan
AU  - Jakovljević, Živana
AU  - Dimitrijević-Branković, Suzana
AU  - Mijin, Dušan
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1304
AB  - In this study, the synthesis of pentyl 2-methylpropanoate employing a commercial lipase from Candida rugosa was investigated, the emphasis being placed on analyzing the effects of various process conditions on the yield of ester. The response surface methodology (RSM) and five-level-five-factor central composite rotatable design (CCRD) were used to evaluate the effects of variables, namely the initial water content, 0.0-2.0% (w/v), the reaction temperature, 35-75°C, the enzyme concentration, 1.0-5.0 g dm-3, the acid/alcohol mole ratio, 1:2-5:2, and the reaction time, 4-48 h, on the yield (%) of ester. The production of pentyl 2-methylpropanoate was optimized and an ester yield response equation was obtained, enabling the prediction of ester yields from known values of the five main factors. It seems that the enzyme concentration, reaction time and acid/alcohol mole ratio predominantly determine the conversion process, while the amount of added water amount had no significant influence on the ester yield. Conversion of around 92 % of the substrate to ester could be realized using a concentration of lipase as low as 4.0 g dm-3 and in a relatively short time (26 h) at 35°C, when a high substrate mole ratio of 2.5 was used.
AB  - U radu su ispitani uticaji različitih procesnih parametara na sintezu pentil-2-metilpropanoata katalizovanu lipazom iz Candida rugosa. U cilju optimizacije enzimske sinteze estara primenjena je metodologija odzivnih površina u skladu sa odabranim centralnim kompozicionim rotabilnim planom (pet faktora na pet nivoa). Ispitani su uticaji procesnih parametara na prinos estra u sledećim intervalima: početnog sadržaja vode (0,0-2,0 %), temperature (35-75°C), koncentracije enzima (1,0-5,0 g dm-3), početnog molskog udela supstrata (1:2-5:2) i reakcionog vremena (4-48 h). Dobijen je adekvatan matematički model na osnovu koga se može predvideti ponašanje sistema u funkciji ovih pet faktora. Pokazano je da koncentracija enzima, početni molski odnos supstrata i reakciono vreme imaju najveći uticaj na proces, dok sadržaj vode ne utiče značajno na prinos estra. Pod optimalnim uslovima enzimske sinteze ostvaren je prinos estra oko 92%.
PB  - Serbian Chemical Society, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - Lipase catalyzed synthesis of flavor esters in non-aqueous media: Optimization of the yield of pentyl 2-methylpropanoate by statistical analysis
T1  - Sinteza mirisnih estara katalizovana lipazama u nevodenoj sredini - optimizacija prinosa pentil-2-metilpropanoata statističkom analizom
EP  - 1151
IS  - 12
SP  - 1139
VL  - 73
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1304
ER  - 

@article{
author = "Knežević-Jugović, Zorica and Bezbradica, Dejan and Jakovljević, Živana and Dimitrijević-Branković, Suzana and Mijin, Dušan",
year = "2008",
abstract = "In this study, the synthesis of pentyl 2-methylpropanoate employing a commercial lipase from Candida rugosa was investigated, the emphasis being placed on analyzing the effects of various process conditions on the yield of ester. The response surface methodology (RSM) and five-level-five-factor central composite rotatable design (CCRD) were used to evaluate the effects of variables, namely the initial water content, 0.0-2.0% (w/v), the reaction temperature, 35-75°C, the enzyme concentration, 1.0-5.0 g dm-3, the acid/alcohol mole ratio, 1:2-5:2, and the reaction time, 4-48 h, on the yield (%) of ester. The production of pentyl 2-methylpropanoate was optimized and an ester yield response equation was obtained, enabling the prediction of ester yields from known values of the five main factors. It seems that the enzyme concentration, reaction time and acid/alcohol mole ratio predominantly determine the conversion process, while the amount of added water amount had no significant influence on the ester yield. Conversion of around 92 % of the substrate to ester could be realized using a concentration of lipase as low as 4.0 g dm-3 and in a relatively short time (26 h) at 35°C, when a high substrate mole ratio of 2.5 was used., U radu su ispitani uticaji različitih procesnih parametara na sintezu pentil-2-metilpropanoata katalizovanu lipazom iz Candida rugosa. U cilju optimizacije enzimske sinteze estara primenjena je metodologija odzivnih površina u skladu sa odabranim centralnim kompozicionim rotabilnim planom (pet faktora na pet nivoa). Ispitani su uticaji procesnih parametara na prinos estra u sledećim intervalima: početnog sadržaja vode (0,0-2,0 %), temperature (35-75°C), koncentracije enzima (1,0-5,0 g dm-3), početnog molskog udela supstrata (1:2-5:2) i reakcionog vremena (4-48 h). Dobijen je adekvatan matematički model na osnovu koga se može predvideti ponašanje sistema u funkciji ovih pet faktora. Pokazano je da koncentracija enzima, početni molski odnos supstrata i reakciono vreme imaju najveći uticaj na proces, dok sadržaj vode ne utiče značajno na prinos estra. Pod optimalnim uslovima enzimske sinteze ostvaren je prinos estra oko 92%.",
publisher = "Serbian Chemical Society, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "Lipase catalyzed synthesis of flavor esters in non-aqueous media: Optimization of the yield of pentyl 2-methylpropanoate by statistical analysis, Sinteza mirisnih estara katalizovana lipazama u nevodenoj sredini - optimizacija prinosa pentil-2-metilpropanoata statističkom analizom",
pages = "1151-1139",
number = "12",
volume = "73",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1304"
}

Knežević-Jugović, Z., Bezbradica, D., Jakovljević, Ž., Dimitrijević-Branković, S.,& Mijin, D.. (2008). Lipase catalyzed synthesis of flavor esters in non-aqueous media: Optimization of the yield of pentyl 2-methylpropanoate by statistical analysis. in Journal of the Serbian Chemical Society
Serbian Chemical Society, Belgrade., 73(12), 1139-1151.
https://hdl.handle.net/21.15107/rcub_technorep_1304

Knežević-Jugović Z, Bezbradica D, Jakovljević Ž, Dimitrijević-Branković S, Mijin D. Lipase catalyzed synthesis of flavor esters in non-aqueous media: Optimization of the yield of pentyl 2-methylpropanoate by statistical analysis. in Journal of the Serbian Chemical Society. 2008;73(12):1139-1151.
https://hdl.handle.net/21.15107/rcub_technorep_1304 .

Knežević-Jugović, Zorica, Bezbradica, Dejan, Jakovljević, Živana, Dimitrijević-Branković, Suzana, Mijin, Dušan, "Lipase catalyzed synthesis of flavor esters in non-aqueous media: Optimization of the yield of pentyl 2-methylpropanoate by statistical analysis" in Journal of the Serbian Chemical Society, 73, no. 12 (2008):1139-1151,
https://hdl.handle.net/21.15107/rcub_technorep_1304 .

TY  - JOUR
AU  - Knežević, Zorica
AU  - Milosavić, Nenad
AU  - Bezbradica, Dejan
AU  - Jakovljević, Živana
AU  - Prodanović, Radivoje
PY  - 2006
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/990
AB  - The present study compares the results of three different covalent immobilization methods employed for immobilization of lipase from Candida rugosa on Eupergit C supports with respect to enzyme loadings, activities and coupling yields. It seems that method yielding the highest activity retention of 43.3% is based on coupling lipase via its carbohydrate moiety previously modified by periodate oxidation. Study of thermal deactivation kinetics at three temperatures (37, 50 and 75 degrees C) revealed that the immobilization method also produces an appreciable stabilization of the biocatalyst, changing its thermal deactivation profile. By comparison of the t(1/2) values obtained at 75 C, it can be concluded that the lipase immobilized via carbohydrate moiety was almost 2-fold more stable than conventionally immobilized one and 18-fold than free lipase. The immobilization procedure developed is quite simple, and easily reproduced, and provides a promising solution for application of lipase in aqueous and microaqueous reaction system.
PB  - Elsevier, Amsterdam
T2  - Biochemical Engineering Journal
T1  - Immobilization of lipase from Candida rugosa on Eupergit (R) supports by covalent attachment
EP  - 278
IS  - 3
SP  - 269
VL  - 30
DO  - 10.1016/j.bej.2006.05.009
ER  - 

@article{
author = "Knežević, Zorica and Milosavić, Nenad and Bezbradica, Dejan and Jakovljević, Živana and Prodanović, Radivoje",
year = "2006",
abstract = "The present study compares the results of three different covalent immobilization methods employed for immobilization of lipase from Candida rugosa on Eupergit C supports with respect to enzyme loadings, activities and coupling yields. It seems that method yielding the highest activity retention of 43.3% is based on coupling lipase via its carbohydrate moiety previously modified by periodate oxidation. Study of thermal deactivation kinetics at three temperatures (37, 50 and 75 degrees C) revealed that the immobilization method also produces an appreciable stabilization of the biocatalyst, changing its thermal deactivation profile. By comparison of the t(1/2) values obtained at 75 C, it can be concluded that the lipase immobilized via carbohydrate moiety was almost 2-fold more stable than conventionally immobilized one and 18-fold than free lipase. The immobilization procedure developed is quite simple, and easily reproduced, and provides a promising solution for application of lipase in aqueous and microaqueous reaction system.",
publisher = "Elsevier, Amsterdam",
journal = "Biochemical Engineering Journal",
title = "Immobilization of lipase from Candida rugosa on Eupergit (R) supports by covalent attachment",
pages = "278-269",
number = "3",
volume = "30",
doi = "10.1016/j.bej.2006.05.009"
}

Knežević, Z., Milosavić, N., Bezbradica, D., Jakovljević, Ž.,& Prodanović, R.. (2006). Immobilization of lipase from Candida rugosa on Eupergit (R) supports by covalent attachment. in Biochemical Engineering Journal
Elsevier, Amsterdam., 30(3), 269-278.
https://doi.org/10.1016/j.bej.2006.05.009

Knežević Z, Milosavić N, Bezbradica D, Jakovljević Ž, Prodanović R. Immobilization of lipase from Candida rugosa on Eupergit (R) supports by covalent attachment. in Biochemical Engineering Journal. 2006;30(3):269-278.
doi:10.1016/j.bej.2006.05.009 .

Knežević, Zorica, Milosavić, Nenad, Bezbradica, Dejan, Jakovljević, Živana, Prodanović, Radivoje, "Immobilization of lipase from Candida rugosa on Eupergit (R) supports by covalent attachment" in Biochemical Engineering Journal, 30, no. 3 (2006):269-278,
https://doi.org/10.1016/j.bej.2006.05.009 . .