Brazilian Journal of Chemical Engineering
versão On-line ISSN 1678-4383
CASTRO, H.F.; OLIVEIRA, P.C. e PEREIRA, E.B.. Influence of substrate partition coefficient on the performance of lipase catalyzed synthesis of citronellyl acetate by alcoholysis. Braz. J. Chem. Eng. [online]. 2000, vol.17, n.4-7, pp.859-866. ISSN 1678-4383. http://dx.doi.org/10.1590/S0104-66322000000400049.
The enzymatic synthesis of selected low molecular weight esters such as acetate esters by direct esterification using acetic acid as acyl donor usually display low yields. The acetic acid changes the polarity of the reaction medium, which in this turn modifies the partitioning of water between the solid phase (enzyme preparation) and the liquid phase (substrate), resulting in its accumulation on the enzyme solid phase. This may reduce the enzyme´s local pH. Therefore, the enzyme active site is modified and the reaction became nearly impossible. Our previous work showed that there is a negative relationship between enzyme activity and substrate partition coefficient (Ps); that is, the higher the substrate partition coefficient the lower the amount of product formed. This work investigated the feasibility of minimizing this inhibition by replacing the esterification reaction for alcoholysis reaction using several acetate esters. This approach enhanced the reaction yields to 46%, which is about 3 times higher than that one obtained in the esterification route.
Palavras-chave : lipase; alcoholysis; citronellyl acetate; partition coefficient.