Enhancing the co-utilization of methanol and CO₂ into 1-butanol by equipping synergistic reductive glycine pathway in Butyribacterium methylotrophicum

The biological fixation of CO₂ and C1-feedstocks like methanol derived from CO₂ are considered as an important technology combating in global warming issues. The microorganisms that can co-assimilate CO₂ and methanol are highly desired. Here, we constructed a synergistic assimilation pathway in Butyribacterium methylotrophicum (B. methylotrophicum) for improved carbon utilization efficiency. Through a transcriptional analysis, the genes involving in the native methanol and CO₂ assimilation pathway, oxidative phosphorylation and amino acid metabolism were significantly up-regulated, indicating the functional cooperation of the pathways in improving cell activity on methanol and CO₂. Ultimately, by overexpressing exogenous genes of adhE2 in recombinant B. methylotrophicum, 1.4 g/L of 1-butanol was successfully synthesized from methanol and CO₂, which was also the highest titer of 1-butanol synthesis using C1-feedstocks. Thus, the design of synergistic methanol assimilation pathway was an effective approach to improve the carbon assimilation capacity of strain for the establishment of C1-feedstock biotransformation platforms.