TY - JOUR
T1 - Isolation of the exoelectrogenic denitrifying bacterium Comamonas denitrificans based on dilution to extinction
AU - Xing, Defeng
AU - Cheng, Shaoan
AU - Logan, Bruce E.
AU - Regan, John M.
N1 - Funding Information:
Acknowledgment This research was supported by a grant from the Air Force Office of Scientific Research.
Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2010/2
Y1 - 2010/2
N2 - The anode biofilm in a microbial fuel cell (MFC) is composed of diverse populations of bacteria, many of whose capacities for electricity generation are unknown. To identify functional populations in these exoelectrogenic communities, a culture-dependent approach based on dilution to extinction was combined with culture-independent community analysis. We analyzed the diversity and dynamics of microbial communities in single-chamber air-cathode MFCs with different anode surfaces using denaturing gradient gel electrophoresis based on the 16S rRNA gene. Phylogenetic analyses showed that the bacteria enriched in all reactors belonged primarily to five phylogenetic groups: Firmicutes, Actinobacteria, α-Proteobacteria, β-Proteobacteria, and γ-Proteobacteria. Dilution-to-extinction experiments further demonstrated that Comamonas denitrificans and Clostridium aminobutyricum were dominant members of the community. A pure culture isolated from an anode biofilm after dilution to extinction was identified as C. denitrificans DX-4 based on 16S rRNA sequence and physiological and biochemical characterizations. Strain DX-4 was unable to respire using hydrous Fe(III) oxide but produced 35 mW/m2 using acetate as the electron donor in an MFC. Power generation by the facultative C. denitrificans depends on oxygen and MFC configuration, suggesting that a switch of metabolic pathway occurs for extracellular electron transfer by this denitrifying bacterium.
AB - The anode biofilm in a microbial fuel cell (MFC) is composed of diverse populations of bacteria, many of whose capacities for electricity generation are unknown. To identify functional populations in these exoelectrogenic communities, a culture-dependent approach based on dilution to extinction was combined with culture-independent community analysis. We analyzed the diversity and dynamics of microbial communities in single-chamber air-cathode MFCs with different anode surfaces using denaturing gradient gel electrophoresis based on the 16S rRNA gene. Phylogenetic analyses showed that the bacteria enriched in all reactors belonged primarily to five phylogenetic groups: Firmicutes, Actinobacteria, α-Proteobacteria, β-Proteobacteria, and γ-Proteobacteria. Dilution-to-extinction experiments further demonstrated that Comamonas denitrificans and Clostridium aminobutyricum were dominant members of the community. A pure culture isolated from an anode biofilm after dilution to extinction was identified as C. denitrificans DX-4 based on 16S rRNA sequence and physiological and biochemical characterizations. Strain DX-4 was unable to respire using hydrous Fe(III) oxide but produced 35 mW/m2 using acetate as the electron donor in an MFC. Power generation by the facultative C. denitrificans depends on oxygen and MFC configuration, suggesting that a switch of metabolic pathway occurs for extracellular electron transfer by this denitrifying bacterium.
UR - http://www.scopus.com/inward/record.url?scp=76649129853&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=76649129853&partnerID=8YFLogxK
U2 - 10.1007/s00253-009-2240-0
DO - 10.1007/s00253-009-2240-0
M3 - Article
C2 - 19779712
AN - SCOPUS:76649129853
SN - 0175-7598
VL - 85
SP - 1575
EP - 1587
JO - Applied Microbiology and Biotechnology
JF - Applied Microbiology and Biotechnology
IS - 5
ER -