Upcycling CO ₂ into Single Cell Protein via an Integrated Electrocatalytic–Biosynthetic System

Artificial photosynthesis systems for food production offer a prospective approach to mitigate climate change and achieve a carbon economy. Herein, we describe an electro-biosystem that couples CO2 electrolysis with microbial engineering to effectively produce single cell protein. A Cu-based catalyst derived from metal–organic frameworks (c-Cu-MOF) was designed for converting CO2 into ethanol and achieves a total current density of −861.81 mA cm–2, with an ethanol partial current density of 187.5 mA cm–2. This result far exceeds the current density of current similar catalysts. Subsequently, metabolic engineering of yeast, via regulation of translation limiting factors and reshaping of cell morphology, is employed to boost protein production, resulting in a 47.06% increase. This integrated electrocatalytic–biosynthetic system achieves conversion of CO2 to protein with a titer of 2.98 g/L in the flask and an electrical energy conversion efficiency of 2.94%, significantly surpassing the energy efficiency of biological CO2 conversion. Our work allows for artificial food synthesis from CO2 and presents a promising blueprint for renewable-electricity-driven CO2 biomanufacturing.