Three multi-enzyme cascade pathways for conversion of C1 to C2/C4 compounds

A feasible and promising carbon reduction strategy is to convert CO 2 into C1 compounds through renewable energy-driven first and then use a multi-enzyme cascade to obtain compounds with higher carbon numbers and market value. In this study, three multi-enzyme cascade pathways for preparing important C2/C4 compounds (ethylene glycol [EG], glycolic acid [GA], and d -erythrose) from methanol were proposed. All pathways use glycolaldehyde as the key intermediate, which can be obtained from methanol through glycolaldehyde synthase and alcohol oxidase cascade. Then, the target compounds can be acquired by adding different enzymes. As a result, 0.90 g/L EG, 0.33 g/L GA, and 53.65 mg/L d -erythrose were produced from methanol. Compared with the titers of EG (6.6 mM) and GA (1.2 g/L) synthesis routes from formaldehyde reported in the literature, the titers of this study (27.58 mM EG and 1.59 g/L GA from formaldehyde) were significantly improved. • Glycolic acid and d -erythrose pathways from CH 3 OH were proposed for the first time • DERA were found to have the function of condensing glycolaldehyde to d -erythrose • GOX were used to synthesize ethylene glycol from glycolaldehyde • ALDH were used to oxidize glycolaldehyde to glycolic acid Under the background of CO 2 is one of the main gases leading to the greenhouse effect and the inexpensive and widespread feedstock. Coupling the renewable energy-driven CO 2 capture technology with multi-enzyme cascade catalytic conversion of C1 compounds to multi-carbon compounds is a promising method for CO 2 utilization. In this case, we successfully constructed three multi-enzyme cascade pathways to synthesize important C2/C4 compounds (ethylene glycol, glycolic acid, and d -erythrose) from C1 compounds. The pathways proposed herein could contribute to realizing the recycling of carbon resources and solving the problems of plastic pollution and energy shortage. They could also provide a new impetus for the design of chemo-bio routes for the efficient conversion of CO 2 into compounds with higher carbon numbers and market value. Junhui et al. successfully constructed three multi-enzyme pathways for synthesizing C2/C4 compounds (ethylene glycol, glycolic acid, and d -erythrose) from C1 compounds. Glycolic acid or d -erythrose pathways were proposed for the first time. Three new kinds of enzymes were found to catalyze intermediate glycolaldehyde to synthesize such C2/C4 compounds.