Degradation of a mixture of polycyclic aromatic hydrocarbons by a defined microbial consortium in a two-phase partitioning bioreactor

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants that are released into the environment via natural and anthropogenic sources. The recalcitrance, as well as mutagenic and/or carcinogenic properties inherent to these compounds has motivated numerous studies to develop potential remediation strategies. Biological treatment methods have been demonstrated to be effective at degrading PAHs and the highest rates of PAH degradation reported in literature to date have been achieved using two-phase-partitioning bioreactors (TPPBs). In this study, the degradation of a mixture of PAHs by a defined microbial consortium of Sphingomonas aromaticivorans B0695 and Sphingomonas paucimobilis EPA505 in a TPPB was examined. An auxanographic differential plating technique was used to monitor changes in the B0695 and EPA505 cell populations during the degradation process. Fermentations conducted using the co-culture showed increased degradation rates of the PAHs compared to the fermentations using the individual species, which suggests a synergistic relationship between the microorganisms. (Abstract shortened by UMI.)...