title: Fenpropathrin biodegradation pathway in Bacillus sp. DG-02 and its potential for bioremediation of pyrethroid-contaminated soils.
abstract: The widely used insecticide fenpropathrin in agriculture has become a public concern because of its heavy environmental contamination and toxic effects on mammals, yet little is known about the kinetic and metabolic behaviors of this pesticide. This study reports the degradation kinetics and metabolic pathway of fenpropathrin in Bacillus sp. DG-02, previously isolated from the pyrethroid-manufacturing wastewater treatment system. Up to 93.3% of 50 mg L(-1) fenpropathrin was degraded by Bacillus sp. DG-02 within 72 h, and the degradation rate parameters qmax, Ks, and Ki were determined to be 0.05 h(-1), 9.0 mg L(-1), and 694.8 mg L(-1), respectively. Analysis of the degradation products by gas chromatography-mass spectrometry led to identification of seven metabolites of fenpropathrin, which suggest that fenpropathrin could be degraded first by cleavage of its carboxylester linkage and diaryl bond, followed by degradation of the aromatic ring and subsequent metabolism. In addition to degradation of fenpropathrin, this strain was also found to be capable of degrading a wide range of synthetic pyrethroids including deltamethrin, λ-cyhalothrin, β-cypermethrin, β-cyfluthrin, bifenthrin, and permethrin, which are also widely used insecticides with environmental contamination problems with the degradation process following the first-order kinetic model. Bioaugmentation of fenpropathrin-contaminated soils with strain DG-02 significantly enhanced the disappearance rate of fenpropathrin, and its half-life was sharply reduced in the soils. Taken together, these results depict the biodegradation mechanisms of fenpropathrin and also highlight the promising potentials of Bacillus sp. DG-02 in bioremediation of pyrethroid-contaminated soils.
authors.affiliation: College of Natural Resources and Environment, South China Agricultural University , Guangzhou 510642, People's Republic of China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Chen
authors.forename: Changqing
authors.initials: C
authors.lastname: Chang
authors.forename: Yinyue
authors.initials: Y
authors.lastname: Deng
authors.forename: Shuwen
authors.initials: S
authors.lastname: An
authors.forename: Yi Hu
authors.initials: YH
authors.lastname: Dong
authors.forename: Jianuan
authors.initials: J
authors.lastname: Zhou
authors.forename: Meiying
authors.initials: M
authors.lastname: Hu
authors.forename: Guohua
authors.initials: G
authors.lastname: Zhong
authors.forename: Lian-Hui
authors.initials: LH
authors.lastname: Zhang
mesh_terms: D001407:Bacillus / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D008401:Gas Chromatography-Mass Spectrometry; D007306:Insecticides / Q000378:metabolism*; D007700:Kinetics; D011722:Pyrethrins / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D012989:Soil Pollutants; C044267:fenpropathrin