Abstract
The lipase from Aspergillus oryzae was modified with a surfactant and then observed to exhibit high catalytic efficiency and enantioselectivity for the kinetic resolution of (RS)-1-phenylethanol. The influential factors of the modified-lipase preparation were investigated, including the surfactant source, the organic cosolvent, and the buffer pH. The optimum modification conditions were found with a surfactant of polyoxyethylene sorbitan monopalmitate, an organic cosolvent of tetrahydrofuran and a phosphate buffer of pH 7.0. In the transesterification of (RS)-1-phenylethanol with vinyl acetate, the surfactant-modified lipase showed excellent enantioselectivity for the R-isomer (E > 200), giving an enantiomeric excess of higher than 99% for (R)-1-phenylethyl acetate at 46.8% conversion with the reaction time of 2 h at 30 °C. The enzymatic activity had barely altered after 30 days even at 50 °C when it was saved in a powdered state. The results indicated that the modification strategy was useful and highly efficient, and that modified A. oryzae lipase was a promising biocatalyst in the kinetic resolution of (RS)-1-phenylethanol.