Degradation of methyl parathion by a mixed bacterial culture and a Bacillus sp. isolated from different soils

The insecticide methyl parathion (MP) is increasingly used as a substitute for parathion, but little information about the microbial degradation and fate of MP in the environment is known. A bacillus sp. capable of mineralizing MP and a mixed bacterial culture were isolated from soils. Both cultures completely degraded MP, but the mixed culture required a second carbon source. No single isolate degraded the chemical although one, Pseudomonas sp, degraded the MP hydrolysis product p-nitrophenol. The results suggest that MP can serve as a sole carbon source for an axenic bacterial culture and/or can be degraded by cometabolism by a bacterial group.