title: Influence of acidic pH on hydrogen and acetate production by an electrosynthetic microbiome.
abstract: 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).
authors.affiliation: Department of Microbiology & Immunology, Marine Biomedicine & Environmental Science Center, Hollings Marine Laboratory, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Edward V
authors.initials: EV
authors.lastname: LaBelle
authors.affiliation: Institute for Genomic and Systems Biology, Argonne National Laboratory, Argonne, Illinois, United States of America.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Marshall
authors.affiliation: Institute for Genomic and Systems Biology, Argonne National Laboratory, Argonne, Illinois, United States of America; Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America; Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America; College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Gilbert
authors.affiliation: Department of Microbiology & Immunology, Marine Biomedicine & Environmental Science Center, Hollings Marine Laboratory, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Harold D
authors.initials: HD
authors.lastname: May
mesh_terms: D000085:Acetates / Q000737:chemistry*; D045855:Acetobacterium; D002245:Carbon Dioxide; D004566:Electrodes; D006859:Hydrogen / Q000737:chemistry*; D064307:Microbiota
chemical_list: D000085:Acetates; D002245:Carbon Dioxide; D006859:Hydrogen