Isolation,identification and degradation characteristics of a PAHs-degrading bacteria from salt-alkaline soil

A predominant PAHs-degrading strain TJB5 was isolated from PAHs-contaminated salt-alkaline soil in Dagang Oilfield of Tianjin,which can use phenanthrene and pyrene as sole carbon source for growth in the selective culture medium.Strain TJB5 was identified as Pantoea agglomerans according to the results of morphology and the phyogenetical analyses of 16S rDNA sequence.The effect of initial concentration of phenanthrene and pyrene,inoculating pH and salinity on degradation efficiencies was investigated.The optimal degradations were determined.The results indicated that the degrading characteristics of the strain were fine.More than 93.3% of phenanthrene and 20% of pyrene in the medium were degraded in the liquid medium with 50 mg/L phenanthrene and pyrene,pH 6.8-9.5 and salinity ranging from 2% to 3% after 15 days at 30 °C.