Isolation, Identification, and Characterization of Omethoate-degrading Pseudomonas abietaniphila ZZY-C13-1-9

  Objective   Omethoate-degrading bacteria were isolated from shed soil to determine their capacities in decomposing the pesticide for possible application in the field.

  Method  Single carbon source culture was used to screen microbes for the potential purpose followed by morphological observation and 16S RNA sequencing for identification. The pesticide-degrading ability of the isolates was determined by molybdate blue spectrophotometry and HPLC, then verified by a shaking flask method in the laboratory. The culture broth for the challenge test containing the selected isolates, one at a time, was artificially added with omethoate at various concentrations.

  Result  A strain, ZZY-C13-1-9, could grow normally when the pesticide was at 1 000 mg·L⁻¹. It was identified as Pseudomonas abietaniphila and capable of degrading 92.3% of omethoate at 400 mg·L⁻¹ level in the nutrient broth within 240 h at the condition of 30 ℃ and 180 r·min⁻¹. In addition, the strain was found to tolerant DDVP and Dipterex in high concentration as well. In a laboratory test at 25–34 ℃ on soil with a moisture content of 25%–30% and omethoate at 200 mg·L⁻¹, ZZY-C13-1-9 decomposed 59.2% of the pesticide in 45 d.

  Conclusion  A bacterium capable of effectively degrading omethoate in soil was successfully isolated, identified, and characterized.