Direct exchange of electrons within aggregates of an evolved syntrophic coculture of anaerobic bacteria.

TitleDirect exchange of electrons within aggregates of an evolved syntrophic coculture of anaerobic bacteria.
Publication TypeJournal Article
Year of Publication2010
AuthorsSummers ZM, Fogarty HE, Leang C, Franks AE, Malvankar NS, Lovley DR
JournalScience
Volume330
Issue6009
Pagination1413-5
Date Published2010 Dec 3
ISSN1095-9203
KeywordsAnaerobiosis, Bacterial Proteins, Biological Evolution, Culture Media, Cytochrome c Group, Electron Transport, Electrons, Ethanol, Fimbriae Proteins, Geobacter, Hydrogen, Microbial Consortia, Microbial Interactions, Mutation, Oxidation-Reduction, Selection, Genetic
Abstract

Microbial consortia that cooperatively exchange electrons play a key role in the anaerobic processing of organic matter. Interspecies hydrogen transfer is a well-documented strategy for electron exchange in dispersed laboratory cultures, but cooperative partners in natural environments often form multispecies aggregates. We found that laboratory evolution of a coculture of Geobacter metallireducens and Geobacter sulfurreducens metabolizing ethanol favored the formation of aggregates that were electrically conductive. Sequencing aggregate DNA revealed selection for a mutation that enhances the production of a c-type cytochrome involved in extracellular electron transfer and accelerates the formation of aggregates. Aggregate formation was also much faster in mutants that were deficient in interspecies hydrogen transfer, further suggesting direct interspecies electron transfer.

DOI10.1126/science.1196526
Alternate JournalScience
PubMed ID21127257