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Title: Influence of acidic pH on hydrogen and acetate production by an electrosynthetic microbiome

Production of hydrogen and organic compounds by an electrosynthetic microbiome using electrodes and carbon dioxide as sole electron donor and carbon source, respectively, was examined after exposure to acidic pH (~5). Hydrogen production by biocathodes poised at -600 mV vs. SHE increased>100-fold and acetate production ceased at acidic pH, but ~5–15 mM (catholyte volume)/day acetate and>1,000 mM/day hydrogen were attained at pH ~6.5 following repeated exposure to acidic pH. Cyclic voltammetry revealed a 250 mV decrease in hydrogen overpotential and a maximum current density of 12.2 mA/cm2 at -765 mV (0.065 mA/cm2 sterile control at -800 mV) by the Acetobacterium-dominated community. Supplying -800 mV to the microbiome after repeated exposure to acidic pH resulted in up to 2.6 kg/m3/day hydrogen (≈2.6 gallons gasoline equivalent), 0.7 kg/m3/day formate, and 3.1 kg/m3/day acetate ( = 4.7 kg CO2 captured).
 [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Medical Univ. of South Carolina, Charleston, SC (United States). Dept. of Microbiology and Immunology, Marine Biomedicine and Environmental Science Center.
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Institute for Genomic and Systems Biology.
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Institute for Genomic and Systems Biology; Univ. of Chicago, Chicago, IL (United States). Dept. of Ecology and Evolution; Marine Biological Lab., Woods Hole, MA (United States); Zhejiang Univ., Hangzhou (China). College of Environmental and Resource Sciences.
  4. Louisiana State Univ. and A & M College, Baton Rouge, LA (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-06CH11357; AR0000089
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 9; Journal Issue: 10; Journal ID: ISSN 1932-6203
Public Library of Science
Research Org:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Country of Publication:
United States
60 APPLIED LIFE SCIENCES; 54 ENVIRONMENTAL SCIENCES hydrogen; microbiome; cathodes; phosphates; graphite; formates; carbon dioxide; electrode potentials