Mediator-free enzymatic electrosynthesis of formate by the Methanococcus maripaludis heterodisulfide reductase supercomplex

Michael Lienemann, Jörg Stefan Deutzmann, Ross Dean Milton, Merve Sahin, Alfred Michael Spormann

Research output: Contribution to journalArticleScientificpeer-review

20 Citations (Scopus)


Electrosynthesis of formate is a promising technology to convert CO2 and electricity from renewable sources into a biocompatible, soluble, non-flammable, and easily storable compound. In the model methanogen Methanococcus maripaludis, uptake of cathodic electrons was shown to proceed indirectly via formation of formate or H2 by undefined, cell-derived enzymes. Here, we identified that the multi-enzyme heterodisulfide reductase supercomplex (Hdr-SC) of M. maripaludis is capable of direct electron uptake and catalyzes rapid H2 and formate formation in electrochemical reactors (-800 mV vs Ag/AgCl) and in Fe(0) corrosion assays. In Fe(0) corrosion assays and electrochemical reactors, purified Hdr-SC primarily catalyzed CO2 reduction to formate with a coulombic efficiency of 90% in the electrochemical cells for 5 days. Thus, this report identified the first enzyme that stably catalyzes the mediator-free electrochemical reduction of CO2 to formate, which can serve as the basis of an enzyme electrode for sustained electrochemical production of formate.
Original languageEnglish
Pages (from-to)278-283
Number of pages6
JournalBioresource Technology
Early online date9 Jan 2018
Publication statusPublished - 1 Apr 2018
MoE publication typeA1 Journal article-refereed



  • Direct electron transfer
  • Electrochemical synthesis of formate
  • Enzyme electrode
  • Heterodisulfide reductase
  • Microbial electrosynthesis

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