Carbon recycling with synthetic CO₂ fixation pathways

Carbon dioxide (CO₂) is the node of alleviating global climate change and supporting living organisms on Earth. Currently, the warming climate and the growing population demand enhanced CO₂ fixation for a sustainable future, which stimulates innovations in biotechnology to tackle these challenges. To this endeavor, synthetic biology and metabolic engineering are enabling a promising approach to engineer synthetic carbon fixation in heterotrophic organisms combining the advantages of both autotrophs and heterotrophs. Here, we review the current advances in constructing synthetic CO₂ fixation pathways and discuss the underlying design principles with confronting challenges. Moreover, we highlight the application scenarios of these designs at different concentrations of CO₂, and how sustainable bioproduction can be improved. We also foresee the future of engineering synthetic carbon fixation pathways for carbon recycling.