Isolation and characterization of fenvalerate degrading strain and optimization of degradation conditions

Bacterial strain BFE-023 with high ability to degrade fenvalerate was isolated from garden soil which contaminated by pyrethroid pesticides. According to physiological and biochemical characteristics and 16 S r DNA sequence,the bacterial strain was identified as Bacillus licheniformis. The main factors influencing fenvalerate degradation were confirmed by using Plackett-Burman design,and the degradation condition was optimized with response surface method. Under the optimal conditions,the degradation of fenvalerate and the generation of 3- phenoxy benzoic acid( 3- PBA) were researched. The results showed that fenvalerate concentration,incubation time and ferric chloride content were the major factors which influencing fenvalerate degradation. In addition,the degradation rate of fenvalerate under the optimized conditions in 60 h reached88.71%,which was similar to predictive value from response surface model(88.78%). The concentration of 3-PBA in the degradation system of fenvalerate was increased obviously at first and then decreased gradually. It was proved that the strain BFE-023 could degrade the intermediate 3-PBA.