title: Long-term operation of microbial electrosynthesis cell reducing CO2to multi-carbon chemicals with a mixed culture avoiding methanogenesis.
abstract: In microbial electrosynthesis (MES), CO2can be reduced preferably to multi-carbon chemicals by a biocathode-based process which uses electrochemically active bacteria as catalysts. A mixed anaerobic consortium from biological origin typically produces methane from CO2reduction which circumvents production of multi-carbon compounds. This study aimed to develop a stable and robust CO2reducing biocathode from a mixed culture inoculum avoiding the methane generation. An effective approach was demonstrated based on (i) an enrichment procedure involving inoculum pre-treatment and several culture transfers in H2:CO2media, (ii) a transfer from heterotrophic to autotrophic growth and (iii) a sequential batch operation. Biomass growth and gradual acclimation to CO2electro-reduction accomplished a maximum acetate production rate of 400mgLcatholyte-1d-1at -1V (vs. Ag/AgCl). Methane was never detected in more than 300days of operation. Accumulation of acetate up to 7-10gL-1was repeatedly attained by supplying (80:20) CO2:N2mixture at -0.9 to -1V (vs. Ag/AgCl). In addition, ethanol and butyrate were also produced from CO2reduction. Thus, a robust CO2reducing biocathode can be developed from a mixed culture avoiding methane generation by adopting the specific culture enrichment and operation procedures without the direct addition of chemical inhibitor.
authors.affiliation: Separation & 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: Sub-department of Environmental Technology, Wageningen University, Wageningen, The Netherlands.
authors.forename: Rustiana
authors.initials: R
authors.lastname: Yuliasni
authors.affiliation: Separation & 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: Sub-department of Environmental Technology, Wageningen University, Wageningen, The Netherlands. Electronic address: david.strik@wur.nl.
authors.forename: David P B T B
authors.initials: DP
authors.lastname: Strik
authors.affiliation: Separation & Conversion Technologies, Flemish Institute for Technological Research (VITO), Mol, Belgium. Electronic address: deepak.pant@vito.be.
authors.forename: Deepak
authors.initials: D
authors.lastname: Pant
mesh_terms: D000085:Acetates / Q000378:metabolism; D052818:Autotrophic Processes; D019149:Bioreactors / Q000382:microbiology*; D002245:Carbon Dioxide / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D003013:Clostridium / Q000254:growth & development / Q000378:metabolism; D004563:Electrochemistry; D004566:Electrodes; D008697:Methane / Q000096:biosynthesis; D010084:Oxidation-Reduction; D013997:Time Factors
chemical_list: D000085:Acetates; D002245:Carbon Dioxide; D008697:Methane
keywords: Autotrophic bioproduction; Biocathode; CO(2) reduction; Microbial electrosynthesis; Wood-Ljungdahl pathway