Functional characterization of a novel microbial esterase identified from the Indian Ocean and its use in the stereoselective preparation of (R)-methyl mandelate

摘要

Genomic mining has identified a novel microbial alkaline esterase from the Indian Ocean.This esterase was overexpressed in E.coli BL21 (DE3) and further functionally characterized.Under optimal conditions (10 mmol/L substrate,pH 6.0,2 h at 40 ℃),this esterase can hydrolyze racemic methyl mandelate to (R)-methyl mandelate with very high optical purity (e.e.＞99％) and yield (nearly 90％).Interestingly,the stereoselectivity of this esterase is opposite to that of two previously reported lipases that can generate (S)-methyl mandelate through the hydrolysis of racemic methyl mandelate.No organic solvents or other additives were required to optimize the optical purity and production of the final chiral product (R)-methyl mandelate,which can potentially simplify the production procedure of (R)-methyl mandelate catalyzed by esterase.