Methylotrophs: from C1 compounds to food.

Microbial protein (MP) is back on the table after decades of slumbering interest. One-carbon (C1) substrates are attractive for MP production due to their efficient production from CO2 and renewable electricity, linking carbon capture to food while circumventing agriculture. Here we compared all reported combinations of C1 (formate/methanol/methane) and microorganisms (bacteria/yeasts) in terms of engineering and biomass quality parameters, focusing on the amino acid match with human requirements. This meta-analysis based on >100 studies suggests that methanol is the most promising C1, and methanol-grown microorganisms seem most nutritional with bacteria and yeasts having different merits. More sustainable MP could be produced if metabolic engineering tools yielding microorganisms with more efficient C1 assimilation pathways and steered amino acid profiles are deployed.