The Degradation Characteristics Of Fenvalerate

Fenvalerate,a kind of pyrethroid pesticides,has been proved efficient,broad-spectrum and most promising insecticide.However,with the widely long-term application of pyrethroid pesticides,massive residues in the agricultural products and food threated to human health and processing of agricultural and sideline products,the accumulation of residues affected the living surroundings,especially.Therefore,after enrichment and acclimation,40 strains with a tolerance to higher concentration of fenvalerate were screened from garden soil which sprayed pyrethroid pesticides for a long time.Through morphological,physiological and biochemical and 16 S rDNA analysis,the efficiency degradation strains BFE-023 and CY-012 were identified as Bacillus licheniformis which was intestinal probiotics and had research value and application potential.The degradation characteristics of strains BFE-023 and CY-012 were able to degrade fenvalerate efficiently and degradate ?-cypermethrin,fenvalerate,permethrin and bifenthrin,simultaneously.Optimization of degradation conditions were researched with HPLC,under the optimized conditions,the degradation rates of fenvalerate by strains BFE-023 and CY-012 reached more than 80%.The culture which was added with ?-cypermethrin,fenvalerate,permethrin and bifenthrin was regarded as the degradation system,four kinds of pyrethroid pesticides were detection simultaneously and the degradation ability of beta-cypermethrin,fenvalerate,permethrin and bifenthrin were different.The results showed that the degradation spectrum of Bacillus licheniformis BFE-023 and CY-012 were wide and the difference of the degradation ability may be related to some special groups and the toxicity of pesticides.Based on the degradation characteristics and degradation spectrum of two strains,the main metabolites of fenvalerate and continuous degradation of metabolites by Bacillus licheniformis BFE-023 were analyzed by GC-MS,the biodegradation pathway was speculated.A-isopropyl-4-chlorobenzene acetic acid and 3-phenoxy phenyl methanol were detected which indicated that the first step in the degradation of fenvalerate was hydrolyzed by carboxylesterase,and then ?-isopropyl-4-chlorobenzene acetic acid were translated into 4-chlorobenzene acetic acid with further reaction.In the degradation system,the presence of benzoic acid and phenol showed that strain BFE-023 could degrade 3-phenoxy benzoic acid.In addition,Bacillus licheniformis BFE-023 had abilities to degrade 4-chlorobenzene acetic acid,benzoic acid and phenol.Thus,fenvalerate was degraded by Bacillus licheniformis BFE-023 completely and the biodegradation pathway of fenvalerate was predicted which laid a foundation for degradation mechanism.The results enriched the degradation bacteria resources of fenvalerate,and provided the basis for the simultaneous detection and degradation of many kinds of pesticides residues in the environment.In addition,the further study of fenvalerate degradation pathway provided a reference for its degradation mechanism and the degradation of other pesticides.The research which possessed important reference value and application prospect laid a foundation for bioremediation.