Isolation And Identification Of Strain Degrading Bacteria Of Organophosphorus Pesticides

Pesticides contribute much to the increase of agricultural production. Organophosphorus pesticides have been gradually substitute organochlorine pesticides since1970s and become the most commonly used pesticides in agriculral pests control. However, the wide utilization of such pesticides has caused serious environmental problems which are threaten people’s health. Therefore, to find and application of mirooranisms degrading organochlorine pesticides will have important effects on environmental conservation.In this paper, a bacterial strain degrading organophosphorus pesticide dichlorvos (dimethyl dichlorovinyl phosphate, DDVP) was isolated from soil samples in vegetable greenhouses in a suburb of Zibo Shandong province. The bacterial strain was identified according to its physiological and biochemical characteristics and16S rDNA sequence analysis, and identified as Pseudomonas fluorescens strain P. The optimal growth temperature, pH value and DDVP degrading efficiency of this strain were investigated, and results showed that the optimal temperature was27℃, the optimum pH was7.0, and the DDVP degrading efficiency under test conditions was61.2%in4days. Mealwhile, organic phosphate hydrolase of P. fluorescens strain P was purified by ammonium sulfate precipitation, ion-exchange chromatography on DEAE-Sepharose4B column followed by gel filtration chromatography on Sperdex-75column. SDS-PAGE analysis indicated the the relative molecular weight of organic phosphate hydrolase of P. fluorescens strain P was33.3kDa. This study will lay a solid foundation for exploring microbial agents and restoring soil polluted by DDVP.