Constraint-based modeling of carbon fixation and the energetics of electron transfer in Geobacter metallireducens.
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.
Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America.
Adam M
AM
Feist
Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America.
Harish
H
Nagarajan
Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, United States of America.
Amelia-Elena
AE
Rotaru
Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, United States of America.
Pier-Luc
PL
Tremblay
Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, United States of America.
Tian
T
Zhang
Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, United States of America.
Kelly P
KP
Nevin
Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, United States of America.
Derek R
DR
Lovley
Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America.
Karsten
K
Zengler
D002244:Carbon / Q000378:metabolism*; D004579:Electron Transport; D004734:Energy Metabolism; D016680:Genome, Bacterial; D045302:Geobacter / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological
D002244:Carbon