Closing the CO₂-to-glycolic acid loop through efficient methanol bioconversion enabled by cofactor-neutral metabolic...

Chemo-biological valorization of CO₂ into value-added chemicals, such as the biodegradable plastic monomer glycolic acid (GA), represents a promising frontier in sustainable manufacturing. However, the realization of this synergistic loop is hindered by the low carbon efficiency of C₁ bioconversion. Herein, we address this challenge by engineering an efficient methanol bioconversion platform that selectively upgrades CO₂-derived methanol into GA. To address metabolic redox constraints inherent to methanol assimilation that severely limit carbon yield, we reprogrammed Komagataella phaffii by constructing a cofactor-neutral biosynthetic route that couples NADPH generation directly to GA formation. Combined with the elimination of competing carbon sinks, this design eradicates the redox constraints that typically limit C₁ assimilation. As a result, carbon flux toward GA surged by 4.6-fold while maintaining cellular fitness. Translating this rewired module to a 5-L bioreactor establishes a benchmark, achieving a titer of 41.2 g/L and the highest reported yield of 0.41 g/g for methanol-only bioconversion. Life-cycle assessment (LCA) reveals a 59.0% lower global warming potential (GWP) relative to fossil-based routes. This study establishes a high-efficiency methanol bioconversion platform for GA production, completing the CO₂-to-GA loop and providing a sustainable route for the utilization of CO₂-derived carbon resources.