Constructing a New Pathway for Ethylene Glycol Biosynthesis and Its Coenzyme Reuse Mechanism

As a high-value bulk chemical, ethylene glycol plays an important role in many fields such as energy, the chemical industry, and automobile manufacturing. At the same time, methanol, as an economical and efficient raw material, has shown great potential in promoting the innovation of bio-based chemicals and fuels. In view of this, this study focused on the excavation and innovative application of enzymes, and successfully designed an efficient artificial cascade catalytic system. The system cleverly converts methanol into ethylene glycol, and the core is composed of methanol dehydrogenase, glycolaldehyde synthase, and lactoaldehyde-pyruvate oxidoreductase. The three enzyme systems work together, which not only simplifies the metabolic pathway, but also realizes the efficient reuse of coenzymes. Subsequently, after ribosome-binding site (RBS) optimization, isopropyl beta-D-Thiogalactoside (IPTG) induction regulation, and methanol concentration adjustment, the concentration of ethylene glycol reached 14.73 mM after 48 h of reaction, and the conversion rate was 58.92%. Furthermore, a new breakthrough in ethylene glycol production was achieved within 48 h by using a two-stage biotransformation strategy and fed-batch feeding in a 5 L fermentor, reaching 49.29 mM, which is the highest yield of ethylene glycol reported so far. This achievement not only opens up a new way for the biotransformation of ethylene glycol, but also lays a foundation for the industrial application in this field in the future.