Chlorpyrifos degradation by Bacillus sp. strain UPMB10 isolated from polluted environment: Analysis and characterization of the metabolite by GC-MS

Abstract

Chlorpyrifos, being a frequently used organophosphate pesticide poses a significant threat to human health due to its prolonged presence in soil, plants, and water, this has raised concern. Consequently, researchers have shifted their attention towards finding methods to mitigate its toxicity or eliminate it from the environment. This has highlighted the importance of bioremediation. This study was aimed at analyzing and characterizing the metabolites of chlorpyrifos degradation by Bacillus sp. strain UPMB10 isolated from polluted environment using Gas Chromatography-Mass Spectrometry. The bacteria were successfully isolated utilizing the enrichment technique in mineral salt media, followed by screening to obtain the best isolate. Identification of the isolate was done at morphological, biochemical, and molecular levels, with a focus on the 16S rRNA gene. Phylogenetic analysis revealed the close relationship between the bacterium and Bacillus sp. strain UPMB10. Optimization (One Factor at A Time) was done to determine best growth conditions of the isolate. The optimal growth conditions obtained include, incubation time of 48 hours, a substrate concentration of 4 g/L, a pH of 7.0, a temperature of 37 °C, and an inoculum size of 2 % (v/v), these quantitative data revealed valuable insights into the factors affecting efficient degradation of pesticide. Gas Chromatography-Mass Spectrometry analysis demonstrated that the bacterium achieved a remarkable degradation efficiency of 99 % after 48 hours of incubation. Notably, Mesitylene and Dimethylmalonic acid were obtained as some of the metabolites of chlorpyrifos degradation. This result provides insight into the transformation of products generated during degradation process. The study finding revealed that Bacillus sp. strain UPMB10 exhibits a remarkable capacity for chlorpyrifos degradation, making it a promising candidate for bioremediation of insecticides and acaricides.