Degrading characteristics of oil-degrading bacteria and its study of petroleum hydrocarbon metabolites

Exploring the community characteristics of petroleum degrading bacteria and revealing the types of petroleum metabolites produced by degrading bacteria play an important role in solving the problem of oil pollution. In this study, the bacterial suspension was extracted from the sludge of the sewage treatment plant, and the efficient dominant bacteria were enriched and cultured by microbial screening. The optimal environmental conditions and kinetic behavior of microbial degradation of petroleum hydrocarbons in groundwater were discussed, and the metabolites of microbial degradation of petroleum hydrocarbons were analyzed. The results showed that the optimum degradation conditions of the strain were as follows: bacterial suspension inoculum: 2%, pH: 7, temperature: 30°C, initial concentration of contaminated water sample: 500 mg/L. Under these conditions, the microbial petroleum hydrocarbon degradation efficiency was 84.7% and followed the first-order kinetics; qualitative and quantitative statistical analysis of the metabolites of the microbial degradation of petroleum hydrocarbons by gas chromatography-time-of-flight mass spectrometry was performed. A total of 10 significantly upregulated products and 12 significantly downregulated products were screened, which were significantly different from the metabolites of the control group. Further microbial community analysis showed that Pseudomonas was dominant in the bacterial suspension, more than 99.5%, which was significantly different from the sludge sample, providing data support for the degradation of petroleum hydrocarbons by Pseudomonas. This study has provided a scientific basis for in situ remediation of petroleum pollution in groundwater.