Interfacial Cofactor Recycling Electroenzymatic Platform for Endergonic CO2 Reduction.

To overcome the thermodynamic barrier of "NADH-dependent CO2 reduction", we developed a bioelectrosynthesis platform via the co-immobilization of CO2 reductase (CR) and diaphorase (DP) on a graphite electrode. A strategic protein engineering approach, utilizing carbon-specific solid-binding peptides (SBPs), enabled oriented enzyme assembly to facilitate efficient interfacial electron transfer. Among the variants, the dual-functionalized system-comprising C-terminal SBP-fused CR and N-terminal ferredoxin (Fd)/SBP-fused DP3-exhibited superior bioelectrocatalytic synergy, achieving a current density of -193.35 µA cm-2. At -0.5 V (vs Ag/AgCl), this integrated interface effectively drove the endergonic reduction process, maintaining continuous cofactor regeneration with an electron transfer efficiency of 39.2%.