Microbial degradation of 4-monobrominated diphenyl ether in an aerobic sludge and the DGGE analysis of diversity.
Polybrominated diphenyl ethers (PBDEs) were applied as flame retardant additives in polymers for many plastic and electronic products. Due to their ubiquitous distribution in the environment, potential toxicity to human and tendency for bioaccumulation, PBDEs have raised public safety concern. In this study we examined the degradation of 4-monobrominated diphenyl ether (4-BDE) in aerobic sludge, as a model for PBDE biodegradation. Degradation of 4-BDE was observed in aerobic sludge. Co-metabolism with toluene or diphenyl ether facilitated 4-BDE biodegradation in terms of kinetics and efficiency. Diphenyl ether seems to perform slightly better as an auxiliary carbon source than toluene in facilitating 4-BDE degradation. During the experiment we identified diphenyl ether by gas chromatography/mass spectrometry(GC/MS), which indicates that an anaerobic debromination has occurred. Bacterial community composition was monitored with denaturing gradient gel electrophoresis. The fragments enriched in 4-BDE-degrading aerobic sludge samples belong to presumably a novel anaerobic Clostridiales species distantly related to all known debrominating microbes. This suggests that 4-BDE biodegradation can occur in anaerobic micro-niche in an apparently aerobic environment, by a previously unknown bacterial species. These findings can provide better understandings of biodegradation of brominated diphenyl ethers and can facilitate the prediction of the fate of PBDEs in the environment.
Department of Life Science, Tzu-Chi University, Hualien, Taiwan.
Chun-Yao
CY
Chen
Chun-Kang
CK
Wang
Yang-Hsin
YH
Shih
D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D004591:Electrophoresis, Polyacrylamide Gel; D005411:Flame Retardants / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology; D055768:Halogenated Diphenyl Ethers / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D014874:Water Pollutants, Chemical