Biocatalytic preparation of ( S)-phenyl glycidyl ether using newly isolated Bacillus megaterium ECU1001

Abstract

A bacterial strain (ECU1001) capable of utilizing phenyl glycidyl ether as sole carbon source and energy source was isolated from soil samples through two steps of screening and was identified as a Bacillus megaterium. The epoxide hydrolase from Bacillus megaterium ECU1001 was biosynthesized in parallel with cell growth and a maximum activity of 31.0 U/l was reached after 30 h of culture when the biomass (DCW) was 9.1 g/l. A temperature of 35°C and pH 8.0 were optimal for the bioconversion. The lyophilized whole cells of Bacillus megaterium ECU1001 could preferentially hydrolyze the ( R)-enantiomer of phenyl glycidyl ether, yeilding ( S)-epoxide and ( R)-diol with high enantioselectivity ( E=47.8). The ( S)-enantiomer of the epoxide remained in the reaction mixture with >99.5% ee (enantiomeric excess) at a conversion of 55.9%. The substrate concentration could be increased up to 60 mM without affecting the ee and ( S)-phenyl glycidyl ether could be obtained with an optical purity of 100% ee and 25.6% yield. Therefore, the method is potentially useful for the preparative resolution of epoxides.