RESUMO
A predominant chrysene-degrading strain was isolated and screened from biological sludge sampled from a coking plant,which can use chrysene as sole carbon source for growth in the selective culture me-dium.The phylogenetic tree of the strain was produced on the basis of morphology observation by SEM,experimental results of physiology and biochemistry and analysis of 16S rDNA sequence.The strain was identified as Achromobacter xylosoxidans.The effect of initial concentration of chrysene solution,inoculat-ing dose and pH on degradation efficiencies was investigated.The results indicate that the degrading charac-teristics of the strain is fine.The optimal degrading conditions are:initial concentration of chrysene solution 40 mg/L,inoculating dose(V/V)10%,pH 7.0~7.5,respectively.Under the optimal conditions,the degrading efficiency can reach more than 80% after 5 days at 30?C.