Cell-Free CO<sub>2</sub> Valorization to C6 Pharmaceutical Precursors via a Novel Electro-Enzymatic Process
Joshua Jack, Haigen Fu, Aaron Leininger, Todd K. Hyster, Zhiyong Jason Ren
Abstract
The healthcare industry emits significant amounts of CO2 and has an imperative need for decarbonization. This study demonstrated a new hybrid electro-enzymatic process that converts waste CO2 into high-value C6 pharmaceutical precursor compounds. A novel three-chamber electrolyzer equipped with a Cu-based gas diffusion electrode converted gaseous CO2 into ethanol at a high current density (40–60 mA/cm2), high selectivity (43–81 mol %), and production rate (368–428 mg/L/h). Purified ethanol from the electrolyzer was then sent to an enzymatic bioreactor where ADH and DERA enzymes upgraded ethanol into C6 statin precursor molecules at high yields (29–35%) via acetaldehyde. Competitive C6 lactol synthesis rates (4.7–5.7 mM/day) and titers (712–752 mg/L) were achieved, demonstrating the potential of the end-to-end process. The C6 lactol product can seamlessly be converted to statins, a class of lipid-lowering medication that is among the largest selling class of drugs in the world. This hybrid process provides a new pathway for CO2 valorization to high-value products and accelerates healthcare sector decarbonization.