Syntrophic interactions improve power production in formic acid fed MFCs operated with set anode potentials or fixed resistances

Dan Sun, Douglas F. Call, Patrick D. Kiely, Aijie Wang, Bruce E. Logan

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Formic acid is a highly energetic electron donor but it has previously resulted in low power densities in microbial fuel cells (MFCs). Three different set anode potentials (-0.30, -0.15, and +0.15V; vs. a standard hydrogen electrode, SHE) were used to evaluate syntrophic interactions in bacterial communities for formic acid degradation relative to a non-controlled, high resistance system (1,000Ω external resistance). No current was generated at -0.30V, suggesting a lack of direct formic acid oxidation (standard reduction potential: -0.40V). More positive potentials that allowed for acetic acid utilization all produced current, with the best performance at -0.15V. The anode community in the -0.15V reactor, based on 16S rDNA clone libraries, was 58% Geobacter sulfurreducens and 17% Acetobacterium, with lower proportions of these genera found in the other two MFCs. Acetic acid was detected in all MFCs suggesting that current generation by G. sulfurreducens was dependent on acetic acid production by Acetobacterium. When all MFCs were subsequently operated at an external resistance for maximum power production (100Ω for MFCs originally set at -0.15 and +0.15V; 150Ω for the control), they produced similar power densities and exhibited the same midpoint potential of -0.15V in first derivative cyclic voltammetry scans. All of the mixed communities converged to similar proportions of the two predominant genera (ca. 52% G. sulfurreducens and 22% Acetobacterium). These results show that syntrophic interactions can be enhanced through setting certain anode potentials, and that long-term performance produces stable and convergent communities. © 2011 Wiley Periodicals, Inc.
Original languageEnglish (US)
Pages (from-to)405-414
Number of pages10
JournalBiotechnology and Bioengineering
Issue number2
StatePublished - Oct 24 2011
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-I1-003-13
Acknowledgements: Contract grant sponsor: King Abdullah University of Science and Technology (KAUST)Contract grant number: KUS-I1-003-13Contract grant sponsor: National Science Foundation Graduate Research FellowshipContract grant sponsor: China Scholarship Council (CSC)
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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