Pseudomonas aeruginosa WJ-1 is a crude-oil degrader that is isolated from Menggulin petroleum reservoir and could utilize the crude oil as sole carbon source to produce some metabolites that enhance its competitiveness and survival in many environments. Pyocyanin extracted from LB culture solution of stain WJ-1 was identified as 1-hydroxyphenazine by using gas chromatograph-mass spectrometry technology. To examine the effects of pyocyanin on microbial community structure and oil degradation, an oil-degrading culture with oil-degrading community T2 was cultivated with or without 0.2 g/L pyocyanin for 32 d. Denaturing gradient gel electrophoresis (DGGE) analysis results showed that a decrease in the microbial community diversity in the pyocyanin-amended cultures compared to that of the unamended cultures. Gas spectrum and oil group experiments indicated that at 32 d the culture without pyocyanin had decreased polycyclic aromatic hydrocarbons and the medium-long fractions of saturated hydrocarbons compared to the pyocyanin-amended culture. The members of the community exhibited the different sensitivity to pyocyanin, corresponding to the different levels of catalase and superoxide dismutase when examined in pure culture. These results demonstrated that pyocyanin influenced the diversity of the microbial community and reduced the potential of oil degradation.

Key words: Pseudomonas aeruginosa, 1-hydroxyphenazine, microbial community, oil degradation