Isolation of an aryloxyphenoxy propanoate (AOPP) herbicide-degrading strain Rhodococcus ruber JPL-2 and the cloning of a novel carboxylesterase gene (feh)

• Main Authors: Liu Hongming, Lou Xu, Ge Zhaojian, Yang Fan, Chen Dingbin, Zhu Jianchun, Xu Jianhong, Li Shunpeng, Hong Qing
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Microbiologia 2015-06-01
• Series: Brazilian Journal of Microbiology
• Subjects: fenoxaprop-P-ethyl; microbial degradation; Rhodococcus ruber JPL-2; FE -hydrolyzing carboxylesterase gene
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822015000200425&lng=en&tlng=en

The strain JPL-2, capable of degrading fenoxaprop-P-ethyl (FE), was isolated from the soil of a wheat field and identified as Rhodococcus ruber. This strain could utilize FE as its sole carbon source and degrade 94.6% of 100 mg L−1 FE in 54 h. Strain JPL-2 could also degrade other aryloxyphenoxy propanoate (AOPP) herbicides. The initial step of the degradation pathway is to hydrolyze the carboxylic acid ester bond. A novel esterase gene feh, encoding the FE-hydrolyzing carboxylesterase (FeH) responsible for this initial step, was cloned from strain JPL-2. Its molecular mass was approximately 39 kDa, and the catalytic efficiency of FeH followed the order of FE > quizalofop-P-ethyl > clodinafop-propargyl > cyhalofop-butyl > fluazifop-P-butyl > haloxyfop-P-methyl > diclofop-methy, which indicated that the chain length of the alcohol moiety strongly affected the hydrolysis activity of the FeH toward AOPP herbicides.