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Characterization of cell-free extracts from fenpropathrin-degrading strain Bacillus cereus ZH-3 and its potential for bioremediation of pyrethroid-contaminated soils

Liu, Jie, Huang, Wenwen, Han, Haitao, She, Changchun, Zhong, Guohua
The Science of the total environment 2015 v.523 pp. 50-58
Bacillus cereus, biodegradation, bioremediation, cyfluthrin, cypermethrin, deltamethrin, fenpropathrin, gas chromatography-mass spectrometry, humans, microorganisms, nontarget organisms, phenol, pollution, pyrethrins, soil, toxicity
Synthetic pyrethroid fenpropathrin has received increasing attention because of its environmental contamination and toxic effects on non-target organisms including human beings. Here we report the degradation characteristics of cell-free extracts from fenpropathrin-degrading strain Bacillus cereus ZH-3 and its potential for pyrethroid bioremediation in soils. 50mg·L−1 of fenpropathrin was decreased to 20.6mg·L−1 by the enzymatic extracts (869.4mg·L−1) within 30min. Kinetic constants Km and Vm were determined to be 1006.7nmol·L−1 and 56.8nmol·min−1, respectively. Degradation products were identified as 3-phenoxybenzaldehyde, α-hydroxy-3-phenoxy-benzeneacetonitrile and phenol by gas chromatography–mass spectrometry (GC–MS). In addition to degradation of fenpropathrin, the cell-free extracts could degrade other pyrethroids including beta-cypermethrin, cyfluthrin, deltamethrin and cypermethrin. Additionally, the reaction conditions were optimized. In the sterile and non-sterile soils, 50mg·kg−1 of fenpropathrin was reduced to 15.3 and 13.9mg·L−1 in 1d, respectively. Sprayed 100 and 300mg·kg−1 of fenpropathrin emulsifiable concentrate (EC), up to 84.6% and 92.1% of soil fenpropathrin were removed from soils within 7d, respectively. Taken together, our results depict the biodegradation characteristics of cell-free extracts from B. cereus ZH-3, highlight its promising potential in bioremediation of pyrethroid-contaminated soils and also provide new insights into the utilization of degrading microbes.