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

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.