P149: Metabolic Engineering of the Ethylmalonyl-CoA Pathway for 1-Butanol Production

As the best understood methylotroph, Methylobacterium extorquens AM1 is a potential platform for converting methanol to biofuels, building on the elucidation of pathways involved in C1 and C2 metabolism and development of tools for metabolic engineering. The ethylmalonyl-CoA pathway, a central methylotrophy pathway, involves several intermediates of biotechnological interest such as crotonyl-CoA that can be withdrawn for production of valuable chemicals.

In this work, we engineered a modified CoA-dependent pathway in Methylobacterium extorquens AM1 to produce 1-butanol. We demonstrated that a strain was able to produce 1-butanol on ethylamine, in which a trans-enoyl-CoA reductase from Treponema denticola and an alcohol dehydrogenase from Clostridium acetobutylicum were used to covert crotonyl-CoA to butanol. In vitro flux analysis and in vivo metabolite analysis showed the functionality of the synthetic pathway and identified problematic steps for future improvement.

This research not only serves as a proof of principle for metabolic engineering of M. extorquens AM1 for producing a valuable chemical, but also tests the concept of using the EMC pathway for 1-butanol production.