Identification and degrading characteristics of PAHs-degrading bacterial strain X20

A bacterial strain X20 was isolated from a mixed microflora which can effectively degrade polycyclic aromatic hydrocarbons (PAHs). This strain was identified as Pseudomonas sp.,based on its morphological observation and 16S rRNA sequence analysis. The study on the degradation of phenanthrene and pyrene by X20,and the effects of medium pH,PAHs initial concentration,and glucose content on the degradation potential of X20 showed that weak alkaline condition favored the degradation of phenanthrene and pyrene by X20,and the optimal pH was 8.0. The effects of glucose concentrations on the degradation changed as parabolic,and 0.2% was the optimal glucose concentration. When the PAHs initial concentrations were 10,20,and 40 mg·L-1,the degradation rates of phenanthrene and pyrene were 56.3%,39.25% and 29.75%,and 41.8%,29.55% and 23.50%,respectively,i.e.,the inhibiting intensity of pyrene to X20 was higher than that of phenanthrene. This study provided a basis for constructing an efficient PAHs-degrading strain and improving the bioremediation effect of PAHs- in situ contaminated soil.