Pretreatment of lipase PS on enantioselective transesterification of (R,S)-ethyl 2-Hydroxyl-4-phenylbutyrate in lsooctane

In the enantioselective transesterification of (R,S)-ethyl 2-hydroxy-4-phenylbutyrate with vinyl acetate in isooctane, Lipase PS pretreated with calcium hydride in iso-octane for 9 h at 4°C and that lyophilized for 8 h were found to be effective in decreasing the hydrolysis side-reaction and enhancing the productivity and optical purity of the remaining (R)-substrate. Anhydrous magnesium sulfate and calcium chloride were not found to be suitable as additives for controlling the water content of the lipase, owing to the low depletion rate of water. Moreover, the very low lipase activity was attributed to aggregation between Lipase PS and calcium chloride.