Understanding the Potential of Microorganisms in Remediating Chlorpyrifos‐Contaminated Soil and Investigating the Molecular Effects of Their Residues in Mammals

Abstract

Biodegradation is a natural process that continuously recycles components into eco-friendly compounds. Despite the toxicity, pesticides such as chlorpyrifos (CPF) are still approved for agricultural uses. Microbial breakdown of the chlorpyrifos component results in 3,5,6-trichloro-2-pyridinol (TCP) and chlorpyrifos oxon, which exert a negligible toxic effect on the ecosystem. This research aims to evaluate the ability of Pseudomonas fluorescens and Rhizobium leguminosarum to chlorpyrifos-degrade and measure CPF residues in male rats fed with treated beans and cultured with bacterial strains. Results of high-performance liquid chromatography (HPLC) analysis conducted for bean plants and soil to estimate the pesticide residues showed the ability of bacteria to degrade CPF. Pseudomonas bacteria exhibited a superior capacity to degrade chlorpyrifos, with a degradation rate of 97.80%, while Rhizobium bacteria achieved an 81.39% degradation rate. The regulation of cytokines in blood samples collected from rats exposed to pesticide stress demonstrated that the addition of Ps and Rh bacteria resulted in upregulation of Interleukin-2 and IL-4 gene expression. Conversely, downregulation of LIF and IL-6 expressions was observed. The expression of neurodegenerative markers (SEPT5, SV2B, AXTN2, and PARK2) was downregulated in brain tissue samples treated with CPF. The combination of Ps and Rh bacteria showed a decrease in TARC levels compared to the CPF-treated group. The study demonstrated that the application of these strains in soil, in conjunction with plant cultivation, can reduce pesticide residues. Consequently, they could be used on a large scale, as they proved to be environmentally safe and effective in the biodegradation of pesticides.