Effects of Cd(II) and Cu(II) on microbial characteristics in2-chlorophenol-degradation anaerobic bioreactors
HUANG Aiqun , CHEN Hao , CHEN Ling , DAI Yalei , ZHAO Jianfu
DOI:
Received July 14, 2007,Revised September 30, 2007, Accepted , Available online
Volume 20,2008,Pages 745-752
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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 e ciency 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+.
