Biodegradation of Chlorpyrifos and 3,5,6-trichloro-2-pyridinol (TCP) by Ochrobactrum sp. CPD-03: Insights from genome analysis on organophosphorus pesticides degradation, chemotaxis and PGPR activity

Organophosphorus pesticides (OPs) are xenobiotic chemicals, present in the environment at unnaturally high concentrations. Chlorpyrifos (CP) is a widespread OP pollutant that poses hazards to non-target organisms along with human beings. The present study reports a newly isolated strain, Ochrobactrum sp. CPD-03 form a paddy field in Bhubaneswar, Odisha, India which could degrade CP in 48 hours with a degradation efficiency of 85-88% in minimal salt medium. The CP degradation at various concentrations (100 mg L-1 to 1000 mg L-1) by CPD-03 was curve fit into a pseudo-first order kinetics [Y= (Y0 - Plateau)*e(-K*X) + Plateau)]. Whole genome analysis indicated the presence of arylesterase (EC 3.1.1.2) and showed the existence of several other genes accountable for the various other xenobiotic compounds degradation. CPD-03 showed chemotactic features towards CP at different concentrations along with other OPs including monocrotophos, coumaphos, diazinon, methyl parathion, and malathion, respectively. Moreover, few new metabolites during CP degradation by CPD-03 were found. This strain was also found to degrade a major metabolite, TCP (3,5,6-trichloro-2-pyridinol) during CP degradation. CPD-03 also displayed potential plant growth promoting activity in inoculated rice seedlings. Taken altogether, our results highlight the potentials of this new isolate Ochrobactrum sp. CPD-03 in bioremediation and application in OP-contaminated ecosystem.