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).
Details
Title
Influence of Acidic pH on Hydrogen and Acetate Production by an Electrosynthetic Microbiome
Author
LaBelle, Edward V. : Medical University of South Carolina Marshall, Christopher W. : Argonne National Laboratory Gilbert, Jack A. : University of Chicago May, Harold D. : Medical University of South Carolina
Data availability statement
The authors confirm that all data underlying the findings are fully available without restriction. The sequence data referred to in the manuscript are now freely available to the public on MG-RAST under Project Electrohydrogenesis Microbiomes: Reactor 4electrode (4562455.3) and Reactor 4supernatant (4562456.3). Additional data files are available in the Supporting Information.
Funding Information
Department of Energy, Advanced Projects Research Agency – Energy, DE-AR0000089 Argonne National Laboratory, Director's Postdoctoral Fellowship
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