Author(s):

AK Sharma, J Pandit, V Gautam and P Shirkot

Abstract: In present study, two bacterial strains from apple orchard soils of Himachal Pradesh were isolated, characterized via biochemical tests followed by molecular characterization using 16S <em>rrna</em> gene technology. Bacterial isolates were identified as <em>Pseudomonas indoloxydans </em>ASK_{3.2<strong> </strong>}and <em>Pseudomonas</em><em> resinovorans</em> strain AST2.2. Both <em>Pseudomonas</em> strains exhibits higher extracellular organophosporus hydrolase (OPH) activities ranging between 0.012-0.165 U/ml and showed resistance to grow at higher concentration of chlorpyrifos. Effect of modification in culture conditions on extracellular OPH activities was studied. In both strains highest OPH activity was observed at pH 8.0, temperature 37 °C, after 48 hrs in presence of glucose as carbon source. Activity of extracellular OPH enzyme in both the strains was found to be enhanced in presence of Co⁺² metal ions, while Cu⁺², Mg⁺² and Fe⁺² ions had lesser effect on OPH activity. SDS was found to be a potent inhibitor for extracellular OPH activity in both strains, while OPH activity was found to be enhanced in presence of DTT. Both strains have chlorpyrifos degrading potential which may be attributed to presence of OPH activities and further purification of this enzyme and its use for bioremediation, biosensor for organophosphorus detection can be tried.

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