Constraint-based modeling of carbon fixation and the energetics of electron transfer in Geobacter metallireducens

PLoS Comput Biol. 2014 Apr 24;10(4):e1003575. doi: 10.1371/journal.pcbi.1003575. eCollection 2014 Apr.

Abstract

Geobacter species are of great interest for environmental and biotechnology applications as they can carry out direct electron transfer to insoluble metals or other microorganisms and have the ability to assimilate inorganic carbon. Here, we report on the capability and key enabling metabolic machinery of Geobacter metallireducens GS-15 to carry out CO2 fixation and direct electron transfer to iron. An updated metabolic reconstruction was generated, growth screens on targeted conditions of interest were performed, and constraint-based analysis was utilized to characterize and evaluate critical pathways and reactions in G. metallireducens. The novel capability of G. metallireducens to grow autotrophically with formate and Fe(III) was predicted and subsequently validated in vivo. Additionally, the energetic cost of transferring electrons to an external electron acceptor was determined through analysis of growth experiments carried out using three different electron acceptors (Fe(III), nitrate, and fumarate) by systematically isolating and examining different parts of the electron transport chain. The updated reconstruction will serve as a knowledgebase for understanding and engineering Geobacter and similar species.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Carbon / metabolism*
  • Electron Transport*
  • Energy Metabolism*
  • Genome, Bacterial
  • Geobacter / genetics
  • Geobacter / metabolism*
  • Models, Biological*

Substances

  • Carbon

Grants and funding

This work was supported by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000087 and by the Office of Science (BER), U.S. Department of Energy under Award Numbers DE-SC0004485 and DE-FC02-02ER63446. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.