title: Application of gas diffusion biocathode in microbial electrosynthesis from carbon dioxide.
abstract: Microbial catalysis of carbon dioxide (CO2) reduction to multi-carbon compounds at the cathode is a highly attractive application of microbial electrosynthesis (MES). The microbes reduce CO2by either taking the electrons or reducing the equivalents produced at the cathode. While using gaseous CO2as the carbon source, the biological reduction process depends on the dissolution and mass transfer of CO2in the electrolyte. In order to deal with this issue, a gas diffusion electrode (GDE) was investigated by feeding CO2through the GDE into the MES reactor for its reduction at the biocathode. A combination of the catalyst layer (porous activated carbon and Teflon binder) and the hydrophobic gas diffusion layer (GDL) creates a three-phase interface at the electrode. So, CO2and reducing equivalents will be available to the biocatalyst on the cathode surface. An enriched inoculum consisting of acetogenic bacteria, prepared from an anaerobic sludge, was used as a biocatalyst. The cathode potential was maintained at -1.1 V vs Ag/AgCl to facilitate direct and/or hydrogen-mediated CO2reduction. Bioelectrochemical CO2reduction mainly produced acetate but also extended the products to ethanol and butyrate. Average acetate production rates of 32 and 61 mg/L/day, respectively, with 20 and 80 % CO2gas mixture feed were achieved with 10 cm2of GDE. The maximum acetate production rate remained 238 mg/L/day for 20 % CO2gas mixture. In conclusion, a gas diffusion biocathode supported bioelectrochemical CO2reduction with enhanced mass transfer rate at continuous supply of gaseous CO2. Graphical abstract ᅟ.
authors.affiliation: Separation and Conversion Technologies, Flemish Institute for Technological Research (VITO), Mol, Belgium.|Sub-department of Environmental Technology, Wageningen University, Wageningen, The Netherlands.
authors.forename: Suman
authors.initials: S
authors.lastname: Bajracharya
authors.affiliation: Separation and Conversion Technologies, Flemish Institute for Technological Research (VITO), Mol, Belgium.
authors.forename: Karolien
authors.initials: K
authors.lastname: Vanbroekhoven
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, Wageningen, The Netherlands.
authors.forename: Cees J N
authors.initials: CJ
authors.lastname: Buisman
authors.affiliation: Separation and Conversion Technologies, Flemish Institute for Technological Research (VITO), Mol, Belgium. deepak.pant@vito.be.
authors.forename: Deepak
authors.identifier: http://orcid.org/0000-0002-1425-9588
authors.initials: D
authors.lastname: Pant
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, Wageningen, The Netherlands.
authors.forename: David P B T B
authors.initials: DP
authors.lastname: Strik
mesh_terms: D000085:Acetates / Q000737:chemistry; D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D019149:Bioreactors; D002244:Carbon; D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D003247:Conservation of Natural Resources; D004566:Electrodes; D004785:Environmental Pollutants; D006859:Hydrogen / Q000737:chemistry; D012722:Sewage / Q000382:microbiology*
chemical_list: D000085:Acetates; D004785:Environmental Pollutants; D012722:Sewage; D002245:Carbon Dioxide; D002244:Carbon; D006859:Hydrogen
keywords: Autotrophic bioproduction; Biocathode; CO2 reduction; Gas diffusion electrode; Microbial electrosynthesis