Microbial detoxification of Pyrethroid insecticide Bifenthrin by selected Fungal strains and Optimizing conditions using Response Surface Methodology

Abstract Bifenthrin is broad spectrum type I pyrethroid insecticide, used broadly for agricultural and urban purposes, yet very little is reported about its biodegradation. Five fungal strains named Aspergillus niger (Asp-N) , Aspergillus flavus (Asp-F ), Aspergillus fumigatus (Asp-Fu), Penicillium chrysogenum (PC) and Lasiodiplodia theobromae (LD) were utilized to degrade bifenthrin for 35 days incubation time. PC is found to be extremely effective in degrading Bifenthrin up to 85%. Furthermore, response surface methodology (RSM) with Box-Behnken design is applied to optimize the degradation conditions with varying pH, temperature (℃) and incubation time (days). The response surface design and analysis of variance depicted the p-value below 0.05 indicating the significance of reaction parameters. The optimal ranges for degrading BF (10 mg/L) by PC were determined to be 30 o C, pH-7 and 24-days incubation period. This fungal strain co-metabolized BF in eutrophic condition within glucose rich medium. The PC degrade BF by hydrolytic cleavage of carboxyl-ester linkage as chromatogram obtained by GCMS with four metabolites. This research provides new insights into the biodegradation of BF by strain Penicillium chrysogenum (PC).