engleski

Evaluation of factors influencing the enantioselective enzymatic esterification of lactic acid in ionic liquid

In this paper esterification of ethanol and lactic acid catalyzed by Candida antarctica B (Novozyme 435) in ionic liquid (Cyphos 104) was studied. The influence of different variables on lipase enantioselectivity and lactic acid conversion was investigated. The variables investigated were ionic liquid mass, water content, alcohol excess and temperature. Using the Design Expert software 23 factorial experimental plan (two level, three factors) was performed to ascertain the effect of selected variables and their interactions on the ethyl lactate enantiomeric excess and lactic acid conversion. The results of the experiments and statistical processing suggest that temperature and alcohol excess have the highest effect on the ethyl lactate enantiomeric excess, while temperature and water content have the highest influence on the lactic acid conversion. The statistical mathematical model developed on the basis of the experimental data calculated that the highest enantiomeric excess achieved in the investigated variable range is 34.3 %, and the highest conversion is 63.8 % at the initial conditions of water content at 8 % ; alcohol excess at 11 and temperature at 30 °C.

lipase ; enantioselectivity ; conversion ; optimization ; experimental plan

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