Integration of biocompatible hydrogen evolution catalyst developed from metal-mix solutions with microbial electrosynthesis

• Published in: Bioelectrochemistry (Amsterdam, Netherlands) Vol. 158; p. 108724
• Main Authors: de Smit, Sanne M., van Mameren, Thomas D., van Zwet, Koen, van Veelen, H. Pieter J., Cristina Gagliano, M., Strik, David P.B.T.B., Bitter, Johannes H.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-08-2024
• Subjects: Acetates - chemistry; Acetates - metabolism; Biocompatible Materials - chemistry; Bioelectric Energy Sources - microbiology; Catalysis; Clostridium - metabolism; CO2 reduction; Electrodes; Hydrogen - chemistry; Hydrogen - metabolism; Hydrogen evolution catalyst; Metals - chemistry; Microbial chain elongation; Microbial electrosynthesis; Microbial trace nutrients; Microbial trace nutrients; Microbial electrosynthesis; Microbial chain elongation; CO2 reduction; Hydrogen evolution catalyst; CO reduction
• ISSN: 1567-5394; 1878-562X
• DOI: 10.1016/j.bioelechem.2024.108724

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•Feasibility of combined chemical and biocatalysis shown for CO2 reduction.•Microbial CO2 reduction starts faster with integrated hydrogen evolution catalyst.•Least metal leaching without Ethylenediaminetetraacetic acid in pre-treatment.
Microbial conversion of CO2 to multi-carbon compounds such as acetate and butyrate is a promising valorisation technique. For those reactions, the electrochemical supply of hydrogen to the biocatalyst is a viable approach. Earlier we have shown that trace metals from microbial growth media spontaneously form in situ electro-catalysts for hydrogen evolution. Here, we show biocompatibility with the successful integration of such metal mix-based HER catalyst for immediate start-up of microbial acetogenesis (CO2 to acetate). Also, n-butyrate formation started fast (after twenty days). Hydrogen was always produced in excess, although productivity decreased over the 36 to 50 days, possibly due to metal leaching from the cathode. The HER catalyst boosted microbial productivity in a two-step microbial community bioprocess: acetogenesis by a BRH-c20a strain and acetate elongation to n-butyrate by Clostridium sensu stricto 12 (related) species. These findings provide new routes to integrate electro-catalysts and micro-organisms showing respectively bio and electrochemical compatibility.