Bioelectrocatalytic Cofactor Regeneration Coupled to CO<sub>2</sub> Fixation in a Redox‐Active Hydrogel for Stereoselective C−C Bond Formation
L. Castañeda-Losada, David Adam, Nicole Paczia, Darren Buesen, Fabian Steffler, Volker Sieber, Tobias J. Erb, Michael Richter, Nicolas Plumeré
Abstract
Abstract The sustainable capture and conversion of carbon dioxide (CO 2 ) is key to achieving a circular carbon economy. Bioelectrocatalysis, which aims at using renewable energies to power the highly specific, direct transformation of CO 2 into value added products, holds promise to achieve this goal. However, the functional integration of CO 2 ‐fixing enzymes onto electrode materials for the electrosynthesis of stereochemically complex molecules remains to be demonstrated. Here, we show the electricity‐driven regio‐ and stereoselective incorporation of CO 2 into crotonyl‐CoA by an NADPH‐dependent enzymatic reductive carboxylation. Co‐immobilization of a ferredoxin NADP + reductase and crotonyl‐CoA carboxylase/reductase within a 2,2′‐viologen‐modified hydrogel enabled iterative NADPH recycling and stereoselective formation of (2S)‐ethylmalonyl‐CoA, a prospective intermediate towards multi‐carbon products from CO 2 , with 92±6 % faradaic efficiency and at a rate of 1.6±0.4 μmol cm −2 h −1 . This approach paves the way for realizing even more complex bioelectrocatalyic cascades in the future.