Development of novel platform E. coli strains for cellodextrin-based production of 3-hydroxypropionate (3HP)

Abstract

The biomass utilization into platform chemicals would economically support the petrochemical industries. The US Department of Energy displayed 12 platform chemicals derived from biomass-based sugars, which can be transformed into new molecules in emerging industrial applications. For present work, selected 3HP has very high global demand of 8 million tons/year in 2020. Recently, the price of glycerol is gradually increasing due to the rapid growth of industrial biodiesel. Therefore, the development of bioprocesses from low-cost cellulosic biomass is required. However, the development of industrial strains that can use cellodextrin, a partial hydrolysis product of cellulose in the hydrolysis process of cellulose, is insufficient. Development of artificial icroorganism platform technology suitable for making biochemical products by fermenting various sugars produced from biomass. To solve the above problems, customized artificial microorganisms capable of simultaneously metabolizing complex sugars such as glucose and xylose, which are the degradation products of cellulose and hemicellulose, as well as cellodextrins, a partial decomposition product of cellulose is required. Malonyl-CoA is a precursor for 3HP biosynthesis and produced by carboxylation of acetyl-CoA with ACCase enzyme. The resulting malonyl-CoA is converted to 3HP via the MCR enzyme. In general, the overproduction of acetyl-CoA / malonyl-CoA biosynthetic genes, elimination of competitive pathways and elimination of the malonyl-CoA degradation pathway increase the concentration of malonyl-CoA, a precursor of 3HP in E. coli. The overall contribution of this project to design an ideal E coli strain for consolidated bioprocessing of 3HP production from biomass.