Dec, 2009
Analyses of Current-Generating Mechanisms of Shewanella loihica PV-4 and Shewanella oneidensis MR-1 in Microbial Fuel Cells
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
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- Volume
- 75
- Number
- 24
- First page
- 7674
- Last page
- 7681
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1128/AEM.01142-09
- Publisher
- AMER SOC MICROBIOLOGY
Although members of the genus Shewanella have common features (e. g., the presence of decaheme c-type cytochromes [c-cyts]), they are widely variable in genetic and physiological features. The present study compared the current-generating ability of S. loihica PV-4 in microbial fuel cells (MFCs) with that of well-characterized S. oneidensis MR-1 and examined the roles of c-cyts in extracellular electron transfer. We found that strains PV-4 and MR-1 exhibited notable differences in current-generating mechanisms. While the MR-1 MFCs maintained a constant current density over time, the PV-4 MFCs continued to increase in current density and finally surpassed the MR-1 MFCs. Coulombic efficiencies reached 26% in the PV-4 MFC but 16% in the MR-1 MFCs. Although both organisms produced quinone-like compounds, anode exchange experiments showed that anode-attached cells of PV-4 produced sevenfold more current than planktonic cells in the same chamber, while planktonic cells of MR-1 produced twice the current of the anode-attached cells. Examination of the genome sequence indicated that PV-4 has more c-cyt genes in the metal reductase-containing locus than MR-1. Mutational analysis revealed that PV-4 relied predominantly on a homologue of the decaheme c-cyt MtrC in MR-1 for current generation, even though it also possesses two homologues of the decaheme c-cyt OmcA in MR-1. These results suggest that current generation in a PV-4 MFC is in large part accomplished by anode-attached cells, in which the MtrC homologue constitutes the main path of electrons toward the anode.
- Link information
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- DOI
- https://doi.org/10.1128/AEM.01142-09
- PubMed
- https://www.ncbi.nlm.nih.gov/pubmed/19837834
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000272429100013&DestApp=WOS_CPL
- URL
- http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=73249148635&origin=inward
- ID information
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- DOI : 10.1128/AEM.01142-09
- ISSN : 0099-2240
- eISSN : 1098-5336
- Pubmed ID : 19837834
- SCOPUS ID : 73249148635
- Web of Science ID : WOS:000272429100013