Recycling CO2 into bioingredients: towards synthetic photo/litho-mixotrophy.

Advances in carbon capture and gas fermentation technologies enable the sustainable production of one-carbon (C1) and C2 organic molecules, such as formate and acetate, by recycling CO2 and organic wastes. Refining C1 and C2 feedstocks into food and other organic ingredients is essential for establishing a carbon-neutral economy. However, current C1/C2-utilizing microbial refinery platforms have yet to achieve ideal carbon efficiency at industrial scales. We critically review progress in innovating metabolic systems across heterotrophic, photosynthetic, and gas fermentation microbial platforms including CO2-fixing and C1-assimilating pathways. Innovative mixotrophic metabolisms, such as photo-mixotrophic and litho-mixotrophic platforms, as well as autotrophic metabolism in heterotrophic platforms, can revolutionize global carbon cycles and enable a sustainable bioeconomy by recycling carbon waste into bioingredients with unprecedented efficiency.