ISOLATION, CHARACTERIZATION AND IDENTIFICATION OF CHLORPYRIFOS TOLERANT PSEUDOMONAS STRAIN EXHIBITING EXTRACELLULAR ORGANO-PHOSPHORUS HYDROLASE (OPH) ACTIVITY FROM APPLE ORCHARD SOILS OF HIMACHAL PRADESHANISH KUMAR SHARMA, AVANI KASTURE JYOTSANA PANDIT AND POONAM SHIRKOT
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 of 16S 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 organo phosphorus 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.
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