Biodegradation of fenoxaprop-P-ethyl (FE) by Acinetobacter sp. strain DL-2 and cloning of FE hydrolase gene afeH

Abstract Fenoxaprop- P -ethyl (FE) is widely used as a post-emergence aryloxyphenoxy propionate (AOPP) herbicide in agriculture. An efficient FE-degrading strain DL-2 was isolated from the enrichment culture and identified as Acinetobacter sp. and the metabolite fenoxaprop acid (FA) was identified by HPLC/MS analysis. The strain DL-2 could also degrade a wide range of other AOPP herbicides. A novel FE hydrolase esterase gene afeH was cloned from strain DL-2 and functionally expressed in Escherichia coli BL21(DE3). The specific activities of recombinant AfeH was 216.39 U mg −1 for FE with K m and V max values of 0.82  μ M and 7.94  μ mol min −1  mg −1 . AfeH could also hydrolyze various AOPP herbicides, p -nitrophenyl esters and triglycerides. The optimal pH and temperature for recombinant AfeH were 9.0 and 50 °C, respectively; the enzyme was activated by Co 2+ and inhibited by Ca 2+ , Zn 2+ , Ba 2+ . AfeH was inhibited strongly by phenylmethylsulfonyl and SDS and weakly by dimethyl sulfoxide.