Spatially-defined intracellular biohybrid for light-driven CO2 conversion

Integrating semiconductor materials with carbon-fixing bacteria in photosynthetic biohybrid systems offers a promising avenue for the solar-driven synthesis of value-added chemicals from carbon dioxide (CO2). However, constructing an efficient biohybrid system that addresses the sluggish photoelectron transfer kinetics, CO2 conversion to multicarbon products, and the biocompatibility of light absorbers is challenging. Here, we describe a novel spatially-defined intracellular biohybrid system in Escherichia coli, integrating light capture, carbon fixation, and fuel production modules for the efficient solar-to-chemical conversion of CO2 into butanediol. By employing protein liquid-liquid phase separation (LLPS) and biomimetic mineralization, we have successfully incorporated biosynthesized doped TiO2 with ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) enzyme within liquid-like condensates, enhancing photogenerated electron transfer and CO2 fixation. This strategy reduced cell death by 30% and improved NAD(P)H regeneration, yielding a 62.11 g/L butanediol yield and a 1.38 mol/mol carbon yield, surpassing previous studies. Our modular engineering approach provides a pathway to enhanced CO2 fixation and regulated photosensitizer control, enabling sustainable biotic-abiotic interface design for energy transduction and catalytic cycles.