An orthogonal metabolic framework for one-carbon utilization

Metabolic engineering often entails concurrent engineering of substrate utilization, central metabolism and product synthesis pathways, inevitably creating interdependency with native metabolism. Here we report an alternative approach using synthetic pathways for C1 bioconversion that generate multicarbon products directly from C1 units and hence are orthogonal to the host metabolic network. The engineered pathways are based on formyl-CoA elongation (FORCE) reactions catalysed by the enzyme 2-hydroxyacyl-CoA lyase. We use thermodynamic and stoichiometric analyses to evaluate FORCE pathway variants, including aldose elongation, alpha-reduction and aldehyde elongation. Promising variants were prototyped in vitro and in vivo using the non-methylotrophic bacterium Escherichia coli. We demonstrate the conversion of formate, formaldehyde and methanol into various products including glycolate, ethylene glycol, ethanol and glycerate. FORCE pathways also have the potential to be integrated with the host metabolism for synthetic methylotrophy by the production of native growth substrates as demonstrated in a two-strain co-culture system. Chou, Lee and Zhu et al. describe a synthetic metabolic pathway for C1 compound utilization using formate, formaldehyde and methanol as substrates.

Automated summary

The study introduces an alternative approach using synthetic pathways for C1 bioconversion, generating multicarbon products directly from formate, formaldehyde and methanol while being orthogonal to the host metabolic network. Variants of the FORCE pathways were evaluated through thermodynamic and stoichiometric analyses, showing promising results both in vitro and in vivo. This synthetic metabolic pathway demonstrates the potential for C1 compound utilization and integration with host metabolism for synthetic methylotrophy.