[Identification of pyrene degrading strains and the degrading characteristics research]

Three bacterial strains J1, J2, J3 which could use pyrene as the sole carbon and energy sources were isolated from soils contaminated with polycyclic aromatic hydrocarbons (PAHs) by enrichment culture. The strains were identified as Pseudomonas aeruginosa, Flavobacterium mizutaii, Brevibacillus parabrevis according to the results of morphology, physiology and the phylogenetical analyses of 16S rDNA sequence. It was observed that the three strains could use pyrene at the concentrations of 50, 100, 200, 500, 1 000 mg/L and after 7 days culture the concentrations of microorganisms in the liquid medium were the highest. Under the treatment of 200 mg/L pyrene the degradation rate of pyrene by strain J1, J2, J3 was 53.04%, 65.03%, 51.02%. The three strains could grow and use pyrene at the culture medium pH 4 to pH 9 and the pH 7 was the best for the microbe growth and the degradation. Compare with the dichloromethane, N, N-dimethylformamide which could increase the solution of pyrene and enhance the degradation of pyrene was the better solvent in the pyrene degradation.