Combining Electrochemical Reduction with Biosynthesis for Directed Conversion of CO<sub>2</sub> into a Library of C3 Chemicals.

Abstract

Electrochemical carbon dioxide (CO₂) reduction presents significant opportunities for sustainable chemical manufacturing. However, conventional electrochemical CO₂ reduction typically produces only C1 or C2 products, and the direct synthesis of C3 chemicals remains a major challenge. In this study, we developed a unique tandem system integrating microbial electroreduction with biosynthesis, demonstrating the feasibility of using CO₂-derived acetic acid as a carbon source for biosynthesis. In Module I, taking advantage of an established perfluorocarbon nanoemulsion strategy for enhanced H₂ delivery, we achieved efficient electrocatalytic CO₂-to-acetate conversion with an acetic acid production rate of 0.34 ± 0.01 g L^-1 day^-1. In Module II, the engineered was established by developing an ultrahigh mutation system to facilitate the screening of desirable microbes with high toxicity tolerance to acetic acid and different products. Various C3 chemicals were efficiently synthesized by this tandem system, including β-alanine (2.1 g/L), acrylic acid (752.4 mg/L), and L-lactic acid (672.9 mg/L), achieving a conversion yield of 0.54-0.72 tons of destined products per ton of CO₂ with an energy consumption of only 51.88-80.7 GJ. This study introduced a novel approach for upcycling CO₂ into a library of high-value C3 chemicals, offering a new approach for achieving carbon neutrality.