Biodegradation of quinalphos by gram negative bacteria Pantoea agglomerans and Acinetobacter sp. dcm5A

Five bacterial strains for biodegradation study were initially isolated from quinalphos exposed soil from cotton field of Indian Agricultural Research Institute, India by Serial dilution and enrichment technique. Amongst them, two strains Pantoea agglomerans and Acinetobacter sp. dcm5A were exposed to different concentrations (50-250 ppm, parts per million) of quinalphos to evaluate their tolerance and the optimum concentration of quinalphos supported growth. Growth kinetics of the isolates was studied by means of optical density of the culture media (150 rpm, rotation per minute) at 30oC for 15 days. The optimal concentration of quinalphos for the growth of Pantoea agglomerans was 100 ppm, while for Acinetobacter sp. dcm5A was 200 ppm. Bacterial strains Pantoea agglomerans and Acinetobacter sp. dcm5A degraded quinalphos 60% and 79.7% respectively in 7 days incubation and 100% degradation by both strains was observed after 13 days of incubation.