Bioremediation of polycyclic aromatic hydrocarbon-contaminated soil by a bacterial consortium and associated microbial community changes

Bioremediation of a PAH-contaminated soil was carried out with a bacterial consortium enriched from the soil. The soil contained 9362.1 mu g kg(-1) of USEPA priority PAHs, 90.6% of which were 4- and 5-ring PAHs. After incubation for 56 days, 20.2% and 35.8% of total PAHs were removed from the soil with the addition of 10% and 20% of a bacterial consortium suspension. The soil microbial population increased in the early days but decreased by the end of the experiment. Denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction (PCR)-amplified bacterial 165 rRNA gene fragments revealed that DGGE profiles of the soil with the addition of the consortium were clustered together and distinct from those of control soil. Sphingobacteria and Proteobacteria were found to be the dominant bacterial groups in the soil according to the sequence analysis of DGGE bands. The results indicate that incubation with a bacterial consortium may be a promising method for bioremediation of PAH-contaminated soils. (C) 2012 Elsevier Ltd. All rights reserved.