Metabolic efficiency of Geobacter sulfurreducens growing on anodes with different redox potentials

Julian Bosch, Keun Young Lee, Siang Fu Hong, Falk Harnisch, Uwe Schröder, Rainer U. Meckenstock

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Microorganisms respiring Fe(III) in the environment face a range of redox potentials of the prospective terminal ferric electron acceptors, because Fe(III) can be present in different minerals or organic complexes. We investigated the adaptation of Geobacter sulfurreducens to this range by exposing the bacteria to different redox potentials between the electron donor acetate and solid, extracellular anodes in a microbial fuel-cell set-up. Over a range of anode potentials from -0.105 to +0.645 V versus standard hydrogen electrode, G. sulfurreducens produced identical amounts of biomass per electron respired. This indicated that the organism cannot utilize higher available energies for energy conservation to ATP, and confirmed recent studies. Either the high potentials cannot be used due to physiological limitations, or G. sulfurreducens decreased its metabolic efficiency, and less biomass per unit of energy was produced. In this case, G. sulfurreducens "wasted" energy at high-potential differences, most likely as heat to fuel growth kinetics.

Original languageEnglish
Pages (from-to)763-768
Number of pages6
JournalCurrent Microbiology
Volume68
Issue number6
DOIs
StatePublished - Jun 2014
Externally publishedYes

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