Isolation,identification and degradation conditions of phenanthrene-degrading bacterium

A set of high efficiency and convenient method was established to isolate phenanthrene-degrading strain,by which,one strain with high and steady phenanthrene-degrading activity was isolated from soil contaminated by heavy oil from Daqing Oilfield.The strain H3 was identified according to its morphological,physiological,biochemical,and 16S rDNA sequence characteristics.The results indicated the phenanthrene-degrading bacterium belonged to the Stenotrophomonas sp..Moreover,the biochemical degradation of phenanthrene was further studied.Under the optimumconditions of 30 ℃,inoculum concentration(10%) and phenanthrene mass concentration of 100 mg.L-1,the degradation rate of phenanthrene reached 98.6% in 12 d.The strain has a good tolerance to high concentrations of the phenanthrene and a large range of pH value.Its maximum tolerated concentration can reach 1 000 mg.L-1,and the optimal pH value is 6.5-9.0.