Abstract: Three pyrene-degrading bacterial strains named D44, D82S and D82Q were isolated from PAHs-contaminated soil in Shenfu Irrigation Area of Shenyang, Northeast China. The strains were identified as Gordonia sp., based on the morphological observation, physiological and biochemical identification, and phylogenetical analysis of 16S rDNA sequences. For all the three stains, their optimal pH was 7, and their growth was obviously inhibited when the pH was lower than 5 or higher than 9. The three strains were capable of utilizing pyrene, benzo［a］pyrene, anthracene, naphthalene, phenanthrene, and fluoranthene as the sole source of carbon and energy. After seven days incubation, the three strains could degrade more than 65% of pyrene with an initial concentration 100 mg·L^-1, and the D44, D82S, and D82Q could degrade 79.6%, 91.3%, and 62.8% of benzo［a］pyrene with an initial concentration 50 mg·L^-1, respectively. PCR amplification indicated that the strains D82Q and D82S possessed alkane monooxygenase gene alkB.

Key words: Gordonia sp., polycyclic aromatic hydrocarbons (PAHs), pyrene, biodegradation