Isolation of the fenoxaprop-ethyl (FE)-degrading bacterium Rhodococcus sp. T1, and cloning of FE hydrolase gene feh.

Abstract

An enrichment culture which completely degraded fenoxaprop-ethyl (FE) was acquired by using FE as sole carbon source. An efficient FE-degrading strain T1 was isolated from the enrichment culture and identified as Rhodococcus sp. Strain T1 could degrade 94% of 100 mg L(-1) FE within 24 h and the metabolite fenoxaprop acid (FA) was identified by HPLC/MS analysis. This strain converted FE by cleavage of the ester bond, but could not further degrade FA. Strain T1 could also efficiently degrade haloxyfop-R-methyl, quizalofop-p-ethyl, cyhalofop-butyl and clodinafop-propargyl. FE hydrolase capable of hydrolysing FE to FA was found in the cell-free extract of strain T1 by zymogram analysis. A novel gene feh encoding FE hydrolase was cloned by shotgun library construction and successfully expressed in Escherichia coli.