Fipronil biodegradation and metabolization by Bacillus megaterium strain E1

Abstract

AbstractBACKGROUNDFipronil is a broad‐spectrum insecticide that is used extensively due to its effective action in pest control. However, environmental studies have shown it has high toxicity towards non‐target organisms as well. In addition, the degradation of fipronil can generate even more toxic and reactive metabolites in the environment. In the present study, bioprospecting for bacteria with the potential to degrade fipronil was performed using fipronil as the sole source of nitrogen and main source of carbon. From samples of corn culture soil with a history of fipronil application, isolation was performed using the microcosm enrichment method.RESULTSBacteria were isolated using fipronil (0.6 g L−1) as the sole nitrogen source and main carbon source. After preliminary tests, isolate E1 was selected and, following sequencing of 16S rRNA, it was found that the isolate E1 was a bacterium of the Bacillaceae family, Bacillus megaterium species. Growth was evaluated by dry biomass and degradation quantified by gas chromatography–mass spectrometry (GC–MS). Strain E1 presented a 94% degradation of fipronil, as well as 91% and 96% degradation of its metabolites fipronil‐sulfide and fipronil‐sulfone, respectively, in 14 days, reducing its initial concentration from 0.6 g L−1 to 0.036 mg L−1.CONCLUSIONThe results showed that bioprospecting of the E1 strain, isolated from soil, showed efficiency in the biodegradation process of fipronil. This strain is a potential candidate for use in bioremediation processes in areas contaminated with fipronil and for use in further studies on the elucidation of the metabolic pathways of fipronil degradation. © 2021 Society of Chemical Industry (SCI).