Engineering artificial photosynthesis based on rhodopsin for CO₂ fixation

This research constructs an artificial photosynthesis system combining rhodopsin's proton-pumping with extracellular electron uptake to drive photoelectrosynthetic CO₂ fixation by *Ralstonia eutropha*. *R. eutropha* is engineered to express an electron transfer pathway from *Shewanella oneidensis* and *Gloeobacter rhodopsin* (GR). GR and the MtrCAB complex from *S. oneidensis* integrate electrons and proton motive force into *R. eutropha*'s electron transport chain (ETC). The system splits water to supply electrons, with GR powering ATP synthesis and reversing the ETC to regenerate NADH/NADPH for biomass synthesis from CO₂. Overexpression of carbonic anhydrase enhances CO₂ fixation. This system advances efficient photosynthesis and redefines microbial rhodopsins' ecological role.

Weiming Tu, Jiabao Xu, Ian P. Thompson, Wei E. Huang