Upgrading Kolbe Electrolysis—Highly Efficient Production of Green Fuels and Solvents by Coupling Biosynthesis and Electrosynthesis

• Published in: Angewandte Chemie International Edition Vol. 61; no. 50; pp. e202210596 - n/a
• Main Authors: Teetz, Niklas, Holtmann, Dirk, Harnisch, Falk, Stöckl, Markus
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 12.12.2022; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Biosynthesis; Carbon Dioxide; Chemical industry; Communication; Communications; Coupling; Cupriavidus necator; Drops (liquids); Electrobiorefinery; Electrodes; Electrolysis; Electrolysis - methods; Electrolytic cells; Fuel additives; Hydrogen; Kolbe Electrolysis; Microorganisms; Octane; Process Coupling; Solvents; Valeric acid; Cupriavidus necator; Biosynthesis; Process Coupling; Electrobiorefinery; Kolbe Electrolysis
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202210596

The chemical industry is transitioning to more sustainable and biobased processes. One key element of this transition is coupling energy fluxes and feedstock utilization for optimizing processes, routes and efficiencies. Here, we show for the first time the coupling of the Kolbe electrolysis at the anode with a subsequent microbial conversion of the cathodically produced co‐product hydrogen. Kolbe electrolysis of valeric acid yields the liquid drop‐in fuel additive n‐octane. Subsequently, the solvent isopropanol is produced by resting Cupriavidus necator cells using gaseous electrolysis products (esp. CO2 and H2). The resting microbial cells show carbon efficiencies of up to 41 % and Coulombic/Faradaic efficiencies of 60 % and 80 % for anodic and cathodic reactions, respectively. The implementation of a paired electrolyser resulted in superior process performances with overall efficiencies of up to 64.4 %. Linking Kolbe electrolysis that converts biobased acids with microbial fermentation of gaseous electrolysis products in a paired electrolyser creates a highly efficient production route for fuel additives and solvents.