Efficient kinetic resolution of para-chlorostyrene oxide at elevated concentration by Solanum lycopersicum epoxide hydrolase in the presence of Tween-20

A putative Solanum lycopersicum epoxide hydrolase, SlEH2, was discovered based on computer-aided analysis. Then, its encoding gene (sleh2) was expressed in E. coli BL21(DE3). The substrate spectrum assay exhibited that E. coli/sleh2, an E. coli transformant expressing SlEH2, possessed the activity of 74.8 U/g wet cell and enantiomeric ratio (E) of 145 towards racemic (rac-) para-chlorostyrene oxide (4a). The scale-up kinetic resolution of 400 mM rac-4a was conducted using 200 mg/mL wet cells of E. coli/sleh2 in the presence of 1% (v/v) Tween-20, retaining (R)-4a with 98.4% ees and 47.1% yields while affording (R)-4b with 92.0% eep and 49.5% yieldp.