Kinetic biosynthesis of L-ascorbyl acetate by immobilized Thermomyces lanuginosus lipase (Lipozyme TLIM).

Thermomyces lanuginosus lipase (Lipozyme TLIM)-catalyzed esterification of L-ascorbic acid was studied. It was suggested that Lipozyme TLIM was a suitable biocatalyst for enzymatic esterification of L-ascorbic acid. Three solvents were investigated for the reaction, and acetone was found to be a suitable reaction medium. Furthermore, it was found that water activity could notably affect the conversion. Moreover, pH memory of Lipozyme TLIM lipase for catalyzing L-ascorbic acid esterification in acetone was observed and the effect of pH on the reaction was estimated. In addition, the influences of other parameters such as substrate mole ratio, enzyme loading, and reaction temperature and reusability of lipase on esterification of L-ascorbic acid were also analyzed systematically and quantitatively. Kinetic characterization of Lipozyme TLIM showed that K(m,a) and V(max) were 80.085 mM and 0.747 mM min(-1), respectively. As a result, Lipozyme TLIM-catalyzed esterification of L: -ascorbic acid gave a maximum conversion of 99%.