Studies On Degradation Of Imidacloprid Endosulfan And Coragen By A Novel Soil Bacterium Pseudomonas Sp Rpt 52

Abstract

Pesticides have become a serious cause for concern due to their toxicity to target as well as non target organisms. Imidacloprid IMD endosulfan ENS and coragen COR are three pesticides which have been used indiscreetly worldwide. Taken together these three pesticides pose a grave threat to the environment. Thus there is an urgent need for mitigation of these pesticides in an environment friendly manner. Bioremediation is one such method where biological species such as bacteria breakdown pesticides into less toxic or non toxic metabolites. newlineIn the current work a bacterial strain was isolated from an agricultural field in Uttarakhand India. The bacterial strain was identified as Pseudomonas sp. by 16S rDNA sequencing and this strain was designated as RPT 52. The bacterium was able to metabolize three different chlorinated pesticides IMD ENS and COR when provided as sole source of carbon in minimal medium. Toxicity studies showed reduction in toxicity of the parent compound when degraded by RPT 52. Laboratory scale soil microcosm studies ascertained that strain RPT 52 is a suitable candidate for bioremediation of ENS and COR contaminated sites. Bioinformatics analysis revealed the involvement of the enzyme xenobiotic reductase xrd in the degradation of these pesticides by the bacterium. xrd was cloned and expressed in a heterologous system. Homology modelling and docking studies revealed active site residues involved in degradation of IMD by xrd. Proteomic analysis of the isolated pesticide degrading bacterium RPT 52 was done both in the presence and absence of pesticides IMD and ENS. A unique protein was expressed in the case of pesticide treated bacterium. This protein was identified as isocitrate lyase which is produced in bacteria under various stresses. qPCR studies revealed upregulation of the gene isocitrate lyase in case of ENS as sole source of carbon to the bacterial strain RPT 52. Thus RPT 52 holds potential for toxicity reduction in the affected environment. newline newline newline newline