Assessment of Biodegradation of Lambda-Cyhalothrin by Bacteria Isolated from Agricultural Soil in Elemere, Kwara State, Nigeria

Lambda-cyhalothrin (LC) is a synthetic pyrethroid (SP) used to control a variety of insect pests. Despite being considered potentially hazardous, LC is used in horticulture, forestry, and agriculture to control a wide variety of insect pests. AN Alternative strategy for reducing pesticide residues is biodegradation, which is both economical and environmentally benign. In this study, LC-degrading bacteria were isolated using an enrichment approach on mineral salt media. Their morphology and certain biochemical characteristics were used to characterize the isolates. For 25 days, the screened isolates' performance was monitored at various intervals using optical density. Gas Chromatography-Mass Spectrometry (GC-MS) analysis was used to identify the LC degraded metabolites. Finally, the screened bacterium was identified using 16S rRNA gene sequencing. The results from the optical density showed an increase in the growth of the isolate from the 5th day to the 15th day, after which it gradually decreased until the 25th day. The GC-MS results revealed the presence of 3-phenoxyphenyl acetonitrile, cyclopropane-1-carboxylic acid, N-(Hydroxymethyl)-acetamide, phenol, phenoxy-benzoate, 3-phenoxy-acetic acid, and phosphonoacetic acid metabolites. The bacterial isolate with the best potential for LC degradation was identified as Klebsiella pneumoniae strain ABS1 and can be explored for bioremediation of LC-contaminated agricultural soils and other synthetic pyrethroids.