Metabolic engineering of Corynebacterium glutamicum for the de novo production of ethylene glycol from glucose

• Two biosynthetic routes were proposed to produce ethylene glycol from glucose.
• Corynebacterium glutamicum was engineered to produce ethylene glycol derived from serine.
• By enzyme screening and metabolic engineering, 3.5 g/L of ethylene glycol was produced.

Development of sustainable biological process for the production of bulk chemicals from renewable feedstock is an important goal of white biotechnology. Ethylene glycol (EG) is a large-volume commodity chemical with an annual production of over 20 million tons, and it is currently produced exclusively by petrochemical route. Herein, we report a novel biosynthetic route to produce EG from glucose by the extension of serine synthesis pathway of Corynebacterium glutamicum. The EG synthesis is achieved by the reduction of glycoaldehyde derived from serine. The transformation of serine to glycoaldehyde is catalyzed either by the sequential enzymatic deamination and decarboxylation or by the enzymatic decarboxylation and oxidation. We screened the corresponding enzymes and optimized the production strain by combinatorial optimization and metabolic engineering. The best engineered C. glutamicum strain is able to accumulate 3.5 g/L of EG with the yield of 0.25 mol/mol glucose in batch cultivation. This study lays the basis for developing an efficient biological process for EG production.