reductive debromination of polybrominated diphenyl ethers by Dehalococcoides

Extensive use of polybrominated diphenyl ethers (PBDEs) has resulted in widespread environmental distribution and concerns remain about risks to human health and ecosystems from legacy PBDE contamination. Though bioremediation has been proven to be a cost-effective and efficient technology for treating halogenated pollutants in situ, application of bioremediation technologies at PBDE-contaminated sites is restricted by a lack of knowledge about functional PBDE-dehalogenating microbes. In the current study, we observed distinct PBDE-dehalogenation activity by three previously isolated Dehalococcoides mccartyi strains (CG1, CG4, and 11a5). PBDE debromination proceeded via distinct pathways in each D. mccartyi strain and involved previously characterized (TceA11a5, PcbA1, and PcbA4) and uncharacterized (11a5_e001) reductive dehalogenases (RDase), suggesting that this phenotype may be more widespread among the Dehalococcoides than is currently recognized.