Gene expression and deletion analysis of mechanisms for electron transfer from electrodes to Geobacter sulfurreducens.

TitleGene expression and deletion analysis of mechanisms for electron transfer from electrodes to Geobacter sulfurreducens.
Publication TypeJournal Article
Year of Publication2011
AuthorsStrycharz SM, Glaven RH, Coppi MV, Gannon SM, Perpetua LA, Liu A, Nevin KP, Lovley DR
JournalBioelectrochemistry
Volume80
Issue2
Pagination142-50
Date Published2011 Feb
ISSN1878-562X
KeywordsBacterial Proteins, Biofilms, Cytochromes, Electrodes, Electron Transport, Electrons, Gene Expression, Geobacter, Graphite, Oligonucleotide Array Sequence Analysis, Oxidation-Reduction, Sequence Deletion
Abstract

Geobacter sulfurreducens is one of the few microorganisms available in pure culture known to directly accept electrons from a negatively poised electrode. Microarray analysis was used to compare gene transcript abundance in biofilms of G. sulfurreducens using a graphite electrode as the sole electron donor for fumarate reduction compared with transcript abundance in biofilms growing on the same material, but not consuming current. Surprisingly, genes for putative cell-electrode connections, such as outer-surface cytochromes and pili, which are highly expressed in current-producing biofilms, were not highly expressed in current-consuming biofilms. Microarray analysis of G. sulfurreducens gene transcript abundance in current-consuming biofilms versus current-producing biofilms gave similar results. In both comparative studies current-consuming biofilms had greater transcript abundance for a gene (GSU3274) encoding a putative monoheme, c-type cytochrome. Deletion of genes for outer-surface proteins previously shown to be essential for optimal electron transfer to electrodes had no impact on electron transfer from electrodes. Deletion of GSU3274 completely inhibited electron transfer from electrodes, but had no impact on electron transfer to electrodes. These differences in gene expression patterns and the impact of gene deletions suggest that the mechanisms for electron transfer from electrodes to G. sulfurreducens differ significantly from the mechanisms for electron transfer to electrodes.

DOI10.1016/j.bioelechem.2010.07.005
Alternate JournalBioelectrochemistry
PubMed ID20696622