Biodegradation of organophosphorus pesticide chlorpyrifos bySphingobacteriumsp. C1B, a psychrotolerant bacterium isolated from apple orchard in Himachal Pradesh of India

A psychrotolerantSphingobacteriumsp. was isolated from the apple orchard situated in the Kufri region of Shimla, Himachal Pradesh, India using an enrichment culture technique having chlorpyrifos (CP) as the sole source of carbon and energy. Based on biochemical characterization and 16S rRNA analysis, the strain was identified asSphingobacteriumsp. C1B. The bacterium C1B was able to degrade chlorpyrifos >= 42 ppm and >= 36 ppm within 14 days at 20 degrees C and 15 degrees C, respectively. The strain was also able to degrade chlorpyrifos <= 35 ppm at 28 degrees C within 14 days. The enzyme organophosphorus hydrolase might be responsible for the initial degradation of CP by the strain C1B. Based on the HPLC and GCMS analysis, a probable degradation pathway has been proposed, which followed the path from chlorpyrifos to 3,5,6-trichloro-2-pyridinol to benzene, 1,3-bis (1,1-dimethylethyl) and then entered into the TCA cycle. Our current study revealed that the bacterium C1B was found to be a useful strain for the degradation of pesticide chlorpyrifos in the cold climatic environment.