Detection of the organophosphate degrading gene opdA in the newly isolated bacterial strain Bacillus pumilus W1

The toxicity of organophosphates to a wide range of organisms necessitates the study of their degradation. We designed a study to isolate an organophosphate-degrading bacterium and to detect the gene involved in the hydrolysis of organophosphates. The bacterial strain was isolated by the enrichment culture technique from organophosphate-contaminated soil, It was identified as Bacillus pumilus W1 based on its biochemical characteristics and found to be able to grow in the presence of methyl parathion (250 ppm). The organophosphate-degrading gene opdA was detected by colony PCR. The specific activity of the organophosphate-degrading enzyme OpdA was analyzed in a cell extract of the bacterial isolate and found to be 0.34 ± 0.14 IU mg-1 protein. The effect of different metals, including Mn2+, Mg2+, Co2+, and Zn2+, on the activity of OpdA was also determined; enzyme activity was enhanced by approximately a factor of 4.84 ± 0.39 in the presence of Mn2+. Degradation of p-nitrophenol was studied under aerobic conditions, and more than 70% p-nitrophenol was degraded within 24 h in the presence of glucose. This is the first report of an opdA gene in this specific B. pumilus strain.