Efficiency of Pseudomonas putida in bioremediation of chlorpyrifos toxicity

Abstract At present, extensive varieties of pesticides are being used but the demand for Organophosphorus pesticide is increasing globally to control insects. Chlorpyrifos is a broad-spectrum, highly toxic, and chlorinated organophosphate insecticide that is synthetic in origin and is normally ester or thiol derivatives of phosphoric. The mode of action involves inhibiting acetyl-cholinesterase leading to the accumulation of acetylcholine causing neurotoxicity. Bacteria capable of degrading the pesticide, chlorpyrifos, were isolated from soil contaminatied with pesticiedes. In this way, three distinct chlorpyrifosdegrading strains of Pseudomonas putidia were isolated, and were characterized using morphological and biochemical analysis. Strain PB1 exhibited the greatest chlorpyrifos degradation rate reach to 100% and was consequently selected for further investigation. Degradation of chlorpyrifos by strain PC1 was rapid at 20 and 37C. Strain PB1 was able to effectively degrade chlorpyrifos in sterilized medium using high inoculum levels. The maximum degradation rate of chlorpyrifos was calculated as 0.08µg/ml to 0.002µg/ml during 6-12 days. Bacteria such as strain PB1, that use chlorpyrifos as a carbon source, could be employed for the bioremediation of sites contaminated with pesticides.