[Isolation and characteristics of PAHs-degrading strains]

The predominant indigenous microbial population and the strain ZL5 PAHS-degrading were obtained by selective enrichment culture from Liaohe viscous oil-contaminated field. The sequence analysis of 16s rDNA showed that strain ZL5 belonged to Sphingomonas sp. The microbial population and the strain could degrade phenanthrene well. 95.28% and 69.24% of phenanthrene in the medium were degraded in 120 hrs. However, the degradation of pyrene by the microbial population or by the strain was low. The degradation rate of phenanthrene or pyrene by the microbial population or the strain was greatly increased while glucose was used as an added substrate. The effect was closely related to the amount of glucose. If the concentration were too high, glucose would show inhibition effect on the degradation of PAHs. Therefore, it was necessary to control the amount of glucose while using glucose as an added substrate to increase degradation of phenanthrene or pyrene.