Engineering carbon fixation in E. coli: from heterologous RuBisCO expression to the Calvin-Benson-Bassham cycle

- Improving carbon fixation is central to meet global sustainability challenges.
- E. coli offers an extended experimental toolbox to enhancing CO2 fixation rates.
- The metabolic network of E. coli was engineered to synthesize biomass from CO2.
- Efforts are underway to reconstruct synthetic autotrophy in E. coli.

Carbon fixation is the gateway of inorganic carbon into the biosphere. Our ability to engineer carbon fixation pathways in living organisms is expected to play a crucial role in the quest towards agricultural and energetic sustainability. Recent successes to introduce non-native carbon fixation pathways into heterotrophic hosts offer novel platforms for manipulating these pathways in genetically malleable organisms. Here, we focus on past efforts and future directions for engineering the dominant carbon fixation pathway in the biosphere, the Calvin-Benson cycle, into the well-known model organism Escherichia coli. We describe how central carbon metabolism of this heterotrophic bacterium can be manipulated to allow directed evolution of carbon fixing enzymes. Finally, we highlight future directions towards synthetic autotrophy.