The oxygen tolerant reductive glycine pathway in eukaryotes: a native methanol, formate and CO2 assimilation pathway in the yeast Komagataella phaffii

The current climate change is mainly driven by excessive anthropogenic CO2 emissions. As industrial bioprocesses depend mostly on food competing organic feedstocks or fossil raw materials, we regard CO2 co-assimilation or the use of CO2-derived methanol or formate as carbon source as pathbreaking contribution to the solution of this global problem. The number of industrially relevant microorganisms that can use these two carbon sources is limited, and even less can concurrently co-assimilate CO2. Hence, we searched for alternative native methanol and native formate assimilation pathways which co-assimilate CO2 in the industrially relevant methylotrophic yeast Komagataella phaffii (Pichia pastoris). Using 13C-tracer-based metabolomics techniques and metabolic engineering approaches we discovered and confirmed a natively active pathway that can perform all three assimilations: the oxygen tolerant reductive glycine pathway. This finding paves the way towards metabolic engineering of formate and CO2 utilisation for the production of proteins, biomass or chemicals in yeast.