Remediation of Chlorpyrifos in Artificially Spiked Soil by Defined Microbial Consortium

Excessive use of pesticides as plant protectants has led to the contamination of ecosystem in all parts of the world. This widespread use of pesticides for agricultural purposes has resulted in the persistence of their residues in various environmental matrices, such as soil, water and air. To remove these residues from the environment bioremediation has been proven a suitable technique for reducing pesticide contamination as microorganisms are capable of mineralizing them completely. Chlorpyrifos is a broad spectrum moderately toxic organophosphorous insecticide. It is widely used in agriculture for pest control and in households as a termicide. Long term exposure to chlorpyrifos residues and its metabolites can affect the human health. A microbial consortium that can utilize Chlorpyrifos as a sole source of carbon and energy was isolated from soil through a novel technique involving an initial enrichment in a column reactor followed by enrichment in a shake flask. A diverse range of microorganisms responsible for Chlorpyrifos degradation has been developed. In the present investigation, a new microbial consortium degrading Quinolphos has been developed. Factors such induction, inoculum level, concentration of the substrate, soil pH, soil moisture etc affecting degradation were also studied. Inoculum level of 500µg protein/mL, and a pH 7.5 at ambient temperature (26–28 ?C) resulted in degradation of Chlorpyrifos upto 50ppm.