Imazamox microbial degradation by common clinical bacteria: Acinetobacter baumannii IB5 isolated from black soil in China shows high potency
LIU Chun-guang | YANG Xin | LAI Yang | LU Hong-gang | ZENG Wei-min | GENG Gui | YANG Feng-shan
Herbicidal residues of imazamox are hazardous to some sensitive rotational aftercrops. The aim of the study was to isolate and identify a microbial strain capable of degrading imazamox. The strain IB5, capable of efficiently degrading imazamox, was isolated from an imazamox-contaminated soybean field in Heilongjiang Province, China. It was found to degrade 98.61% of 400 mg L–1 imazamox within 48 h by high-performance liquid chromatograph. Through morphological, physiological and biochemical characterization, and the 16S rDNA sequencing, the strain was identified as Acinetobacter baumannii. An optimal degradation condition was obtained and verified: 400 mg L–1 imazamox, 0.1% (volume ratio) initial inoculum, 37°C and pH 7.0. Four main products were captured in the liquid chromatograms and mass spectra, and a pathway for imazamox degradation by IB5 was proposed. This work provides a new suitable candidate for imazamox biodegradation and theoretical evidence for imazamox residue bioremediation. A. baumannii is a common clinical bacteria, but its imazamox-degrading feature has not been reported previously.
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