Self‐Assembled Protein Cages in Living Bacterial Photocatalysis: Modular Design Achieves Selective Regeneration of NADH and Efficient CO ₂ Fixation

Abstract The use of predesigned bioengineered proteins to construct spatially confined structures enables efficient integration of biological and nanomaterial components, offering new scientific directions for nano‐biohybrid systems. The unique properties of nanomaterials can alter the original biological paradigm to enable new metabolic pathways or new activation triggers. Inspired by the cascade process of “light‐driven electron transfer–cofactor regeneration–carbon assimilation” in natural photosynthesis, this study constructs a ternary synergistic system comprising a photocatalyst, protein cage, and live bacteria. By integrating a light‐induced electron module, a protein cage protective module, and a metabolic module, this system achieves selective NADH generation and efficient CO 2 fixation. The incorporation of the protein cage not only enhances enzyme stability but also physically separates the photosensitizer from the enzyme, thereby preserving the enzyme's conformational integrity and improving electron utilization efficiency. This biomimetic system demonstrates a significant enhancement in CO 2 ‐to‐formate conversion efficiency (6.8‐fold increase), showcasing robust functional integration potential and light energy utilization capability. This strategy opens new avenues for light‐driven green chemical synthesis, provides a paradigm for the deep integration of synthetic biology and green materials science, and lays a solid foundation for the development of next‐generation artificial photosynthetic cell factories.