Sustainable hybrid photo/electro-enzyme systems for CO2 conversion

Carbon dioxide (CO 2 ), as an abundant and renewable carbon feedstock, holds immense potential for sustainable biomanufacturing. However, natural carbon fixation pathways, such as the Calvin-Benson-Bassham (CBB) cycle and the reverse tricarboxylic acid (rTCA) cycle, suffer from intrinsic limitations, including low catalytic efficiency, high ATP consumption, and oxygen sensitivity. Recent advances in synthetic biology and metabolic engineering have pioneered artificial pathways (e.g., the crotonyl-CoA/ethylmalonyl-CoA/hydroxybutyryl-CoA (CETCH) cycle) that bypass central metabolism, achieving higher fixation rates with reduced ATP consumption. Concurrently, photocatalytic and electrocatalytic systems have emerged as complementary strategies to address cofactor dependency and CO 2 activation thermodynamic barriers. This review synthesizes breakthroughs in (i) rational design for CO 2 conversion pathway optimization, (ii) photocatalysis, and (iii) electrocatalysis for CO 2 activation and cofactor regeneration. By integrating these disciplines, synergistic systems achieve unprecedented efficiency in converting CO 2 to Cn compounds (e.g., ethanol, glyoxylate, sugar, starch) and establish a foundation for scalable carbon-negative biotechnologies. However, challenges remain, including enzyme denaturation under operational stresses, inefficiencies in multi-enzyme cascades due to kinetic mismatches, and the need for sustainable metrics to ensure net-negative carbon footprints. Future research should prioritize material innovation, CO 2 assimilation system integration and optimization to unlock higher efficiency CO 2 conversion, aligning with global decarbonization goals while producing high-value chemicals. • Artificial CO2 assimilation pathway with novel carbon conversation enzyme achieved higher efficiency. • Advanced photo/electrocatalysis coupled with enzyme promoted CO2 activation. • Promising hybrid photo/electro-biocatalysis systems sequester CO2 while synthesizing high-value chemicals.