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

Niklas Teetz, Dirk Holtmann, Falk Harnisch, Markus Stöckl

 Angew. Chem. Int. Ed. 2022,e202210596, doi: 10.1002/anie.202210596

Angew. Chem. 2022 ,e202210596, doi: 10.1002/ange.202210596

Abstract

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 electrolyzer resulted in superior process performances with overall efficiencies of up to 64.4%.

 

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