Abstract: By using selective enrichment culture with pyrene as the sole carbon source, a pyrene-degrading bacterial strain ZQ₅ was isolated from the oil-contaminated soil in Shenfu Irrigation Area. The strain was identified as Stenotrophomonas sp., based on its morphological, physiological, and biochemical characteristics, and similarity identification of 16S rDNA sequence. The pyrene-degrading characteristics and the effects of culture condition on the degrading efficiency of the strain were investigated by shaking flask culture. After shaking culture with the initial concentration of pyrene being 100 mg·L^-1 at 30 ℃ for 10 days, the degradation rate of pyrene was 91.2%. Adding 100 mg·L^-1 of alicylic acid into culture medium could enhance the degrading efficiency of the strain. For the degradation of pyrene by ZQ₅, the optimal medium pH was 7-8, and the optimal salt concentration was lower than 2%.

Key words: pyrene, biodegradation, PAHs, Stenotrophomonas sp., soil microbial community structure, PLFA, natural forest of Castanopsis fabri,  Cunninghamia lanceolata plantation.