title: Effects of Cd(II) and cu(II) on microbial characteristics in 2-chlorophenol-degradation anaerobic bioreactors.
abstract: The effects of Cd2+ and Cu2+ at 300 mg/L on anaerobic microbial communities that degrade 2-cholorophenol (2-CP) were examined. Based on the polymerase chain reaction (PCR) of 16S rDNA, bacterial community diversity and archaeal community structure were analyzed with denaturing gradient gel electrophoresis (DGGE) and cloning, respectively. Degradation capabilities of the anaerobic microbial community were drastically abated and the degradation efficiency of 2-CP was reduced to 60% after shock by Cu2+ and Cd2+, respectively. The bacterial community structure was disturbed and the biodiversity was reduced after shock by Cu2+ and Cd2+ for 3 d. Some new metal-resistant microbes which could cope with the new condition appeared. The sequence analysis showed that there existed common Archaea species in control sludge and systems when treated with Cu2+ and Cd2+, such as Methanothrix soehngenii, Methanosaeta concilii, uncultured euryarchaeote, and so on. Both the abundance and diversity of archaeal species were altered with addition of Cd2+ and Cu2+ at high concentration. Although the abundance of the predominant archaeal species decreased with Cd2+ and Cu2+ addition for 3 d, they recovered to some extent after 10 d. The diversity of archaeal species was remarkably reduced after recovery for 10 d and the shift in archaeal composition seemed to be irreversible. The 2-CP-degradation anaerobic system was more sensitive to Cu2+ than Cd2+.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. huangaiqun2033@sina.com
authors.forename: Aiqun
authors.initials: A
authors.lastname: Huang
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Lingl
authors.initials: L
authors.lastname: Chen
authors.forename: Yalei
authors.initials: Y
authors.lastname: Dai
authors.forename: Jianfu
authors.initials: J
authors.lastname: Zhao