Remediation of chlorpyrifos in soil using immobilized bacterial consortium biostimulated with organic amendment

Pesticides released into the environment have become a danger to the mother earth arousing a worldwide alert to initiate remediation at the point sources of contamination in an ecofriendly way. The recent advances in bioremediation technology using microbial consortium have been found effective for the treatment of pesticides in soil. In this context, the present study evaluates and compares the ability of an assembled bacterial consortium C5 (Staphylococcus warneri CPI 2, Pseudomonas putida CPI 9 and Stenotrophomonas maltophilia CPI 15) to remove chlorpyrifos in soil in its free cells state and immobilized state on wood chips. Chlorpyrifos degradation by C5 was studied via a pot study experiment with completely randomized block design. A comparative analysis of degradation, total microbial count and dehydrogenase activity was performed in soils with and without chlorpyrifos application history and under amendment with a mix of cow dung and mushroom spent as biostimulant. Based on ANOVA results, the treatments T3 and T7, both received immobilized C5 and biostimulant were found to be the best giving complete degradation of 125 mg kg(-1) of chlorpyrifos in 30 days. All the studied factors - degradation, microbial count and dehydrogenase activity were higher in the soil with chlorpyrifos exposure history. The results presented here highlight the potential use of wood chip immobilized consortium C5 biostimulated with a mix of cow dung and mushroom spent for remediating chlorpyrifos effectively in contaminated soil.