Microbial Electricity Generation Enhances Decabromodiphenyl Ether (BDE-209) Degradation

We thank Hao Yu and Ye Deng at the University of Oklahoma for assistance with GeoChip hybridization and data pre-processing. We also thank Professor Bixian Mai and Dr. Leheng Yu in Guangzhou Institute of Geochemistry, CAS, for their helps in PBDE congener analyses.Conceived and designed the experiments: MYX JG GPS. Performed the experiments: YGY MYX. Analyzed the data: MYX YGY. Contributed reagents/materials/analysis tools: ZLH JZZ. Wrote the paper: MYX YGY ZLH.Due to environmental persistence and biotoxicity of polybrominated diphenyl ethers (PBDEs), it is urgent to develop potential technologies to remediate PBDEs. Introducing electrodes for microbial electricity generation to stimulate the anaerobic degradation of organic pollutants is highly promising for bioremediation. However, it is still not clear whether the degradation of PBDEs could be promoted by this strategy. In this study, we hypothesized that the degradation of PBDEs (e.g., BDE-209) would be enhanced under microbial electricity generation condition. The functional compositions and structures of microbial communities in closed-circuit microbial fuel cell (c-MFC) and open-circuit microbial fuel cell (o-MFC) systems for BDE-209 degradation were detected by a comprehensive functional gene array, GeoChip 4.0, and linked with PBDE degradations. The results indicated that distinctly different microbial community structures were formed between c-MFCs and o-MFCs, and that lower concentrations of BDE-209 and the resulting lower brominated PBDE products were detected in c-MFCs after 70-day performance. The diversity and abundance of a variety of functional genes in c-MFCs were significantly higher than those in o-MFCs. Most genes involved in chlorinated solvent reductive dechlorination, hydroxylation, methoxylation and aromatic hydrocarbon degradation were highly enriched in c-MFCs and significantly positively correlated with the removal of PBDEs. Various other microbial functional genes for carbon, nitrogen, phosphorus and sulfur cycling, as well as energy transformation process, were also significantly increased in c-MFCs. Together, these results suggest that PBDE degradation could be enhanced by introducing the electrodes for microbial electricity generation and by specifically stimulating microbial functional genes.Yeshttp://www.plosone.org/static/editorial#pee