Ethylene glycol and glycolic acid production by wild-typeEscherichia coli

Ethylene glycol and glycolic acid are bulk chemicals with a broad range of applications. The ethylene glycol and glycolic acid biosynthesis pathways have been produced by microorganisms and used as a biological route for their production. Unlike the methods that use xylose or glucose as carbon sources, xylonic acid was used as a carbon source to produce ethylene glycol and glycolic acid in this study. Amounts of 4.2 g/L of ethylene glycol and 0.7 g/L of glycolic acid were produced by a wild-typeEscherichia coliW3110 within 10 H of cultivation with a substrate conversion ratio of 0.5 mol/mol. Furthermore,E. colistrains that produce solely ethylene glycol or glycolic acid were constructed. 10.3 g/L of glycolic acid was produced byE. coli Delta yqhD+aldA, and the achieved conversion ratio was 0.56 mol/mol. Similarly, theE. coli Delta aldA+yqhDproduced 8.0 g/L of ethylene glycol with a conversion ratio of 0.71 mol/mol. Ethylene glycol and glycolic acid production byE. colion xylonic acid as a carbon source provides new information on the biosynthesis pathway of these products and opens a novel way of biomass utilization.