ISOLATION, CHARACTERIZATION AND IDENTIFICATION OF CHLORPYRIFOS TOLERANT PSEUDOMONAS STRAIN EXHIBITING EXTRACELLULAR ORGANO-PHOSPHORUS HYDROLASE (OPH) ACTIVITY FROM APPLE ORCHARD SOILS OF HIMACHAL PRADESH

摘要

A bacterial strain ASK3.2 isolated from chlorpyrifos contaminated apple orchard soil was found to be highly effective in degrading chlorpyrifos. On the basis of morphology; physiological characteristics, biochemical tests, and phylogenetic analysis of16S rRNA sequence, the isolate was identified as Pseudomonas indoloxydans. It was observed that P. indoloxydans ASK3.2 was able to utilize chlorpyrifos as a sole carbon and energy source and grows on a medium containing concentration up to 400 mg L"1. This strain ASK3.2 exhibited high extracellular organophosphorus hydrolase (OPH) activity at 37°C with pH 8.0, after 48 hrs incubation period. Gas chromatography-flame ionization detector (GC-FID) studies revealed that P. indoloxydans ASK3.2 degraded chlorpyrifos. The strain ASK3.2 showed 82.72 % degradation of chlorpyrifos after 96 hrs. Intermediates of chlorpyrifos degradation were identified using gas chromatography mass spectroscopy (GC-MS). These results indicate that Pseudomonas indoloxydans ASK3.2 is a prospective strain which can be employed in bioremediation of chlorpyrifos contaminated environments.