S122: Development of a sustainable process for the production of 1,2-propanediol

1,2-propanediol or propylene glycol is a bulk chemical with an annual market of 1.7 million tons worth $ 2.2 billion. It is used in unsaturated polyester resins, de-icing and antifreeze liquids and personal care products. Currently the molecule is produced by a chemical process relying on crude-oil derived propylene as a raw material. As an alternative to the chemical process, we have developed a biological process for the conversion of sugars to 1,2-propanediol at high yield. For this purpose E. coli was initially engineered for the co-production of 1,2-propanediol and acetate and the strain was optimized by evolution. The evolved strain was characterized physiologically and genetically and the terminal biosynthesis pathway of 1,2-propanediol was elucidated. Molecular and biochemical characterization of the corresponding evolved enzymes showed that the kinetic properties are in agreement with the physiological properties of the evolved strain. In a rational approach integrating the evolved enzymes an industrial strain was constructed that served for the development of a fermentation process at pilot scale. This strain was then modified for the utilization of sucrose. The resulting strain produced 1,2-propanediol with higher titer, yield and productivity offering a sustainable production process for this bulk chemical.