Biodegradative activities of some indigenous farm soil bacteria on selected pesticides

Abstract

Pesticides play a pivotal role in contemporary agriculture, serving as vital tools for safeguarding crops against pest infestations and diseases. Nevertheless, the widespread application of pesticides has raised concerns due to their potential unintended consequences on the environment and human health. This study investigates the variability in bacterial populations in farm soil and their pesticide-degrading potentials. The isolates were characterized using different conventional and molecular methods. The bacterial isolates were tested against organophosphorus pesticides using quantitative and qualitative methods at different concentrations to detect their degradative ability. Three bacterial isolates were selected and molecularly characterized by the 16S rDNA technique. The metabolites produced from the degraded organophosphorous pesticides were analyzed using the Fourier Transform Infrared Spectrophotometer (FTIR). Variations were observed in both Total Bacteria Count (TBC) (10.18 - 11.00 Log10 CFU/ml) and Pesticide-degrading Bacteria Count (PDBC) (6.09 - 8.42 Log10 CFU/ml) among different soil samples. The three selected isolates were identified as Pseudomonas aeruginosa, Bacillus subtilis and Bacillus thuringiensis based on 16Sr RNA gene sequences. These bacterial strains exhibited distinct varied susceptibility patterns at varying concentrations of Methomyl and Emamectin Benzoate. This research highlights the role of specific bacterial strains in pesticide degradation and their potential environmental implications.