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Fenpropathrin Biodegradation Pathway in Bacillus sp. DG-02 and Its Potential for Bioremediation of Pyrethroid-Contaminated Soils
journal contribution
posted on 2014-03-12, 00:00 authored by Shaohua Chen, Changqing Chang, Yinyue Deng, Shuwen An, Yi Hu Dong, Jianuan Zhou, Meiying Hu, Guohua Zhong, Lian-Hui ZhangThe
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.