Production Of 3-Hydroxypropionic Acid From Glucose By Recombinant Strain Of Escherichia Coli

3-Hydroxypropionic acid or 3-Hydroxypropanoate (3-HP) is an important platform chemical. The bifunctionality of 3-HP owing to the presence of a carboxyl and hydroxyl group, makes it a versatile agent for organic synthesis. In particular, the polymer produced from the self-condensation of 3-HP, [poly (3-hydroxypropionic acid)], has good biocompatibility and biodegradability, and can be used for the manufacture of surgical products and drug-releasing materials. 3-HP can be produced by chemical routes, wild microbial metabolism and biological pathways.This studay aims at constructing recombinant Escherichia coli to produce 3-HP from glucose. The enzyme genes involved in the pathway from succinate to 3-HP were cloned, which included succinyl-CoA synthetase (SucCD), methylmalonyl-CoA mutase (ScpA), methylmalonyl-CoA epimerase (MMCE), methylmalonyl-CoA decarboxylase (ScpB), acryloyl-CoA reductase (AcuI), acyl-CoA dehydrogenase (ACD), putative enoyl-CoA hydratase (PaaF), enoyl-CoA hydratase (ECH) and 3-hydroxyisobutyryl-CoA hydrolase (HIBCH). Further more, two recombinant strains, E. coli BL21(pYES2-SSMSAEH) and E. coli BL21(pET-28a-ASSSPH), were constructed via in vivo homologous recombination in Saccharomyces cerevisiae and in vitro homologous recombination by a commercial kit. Unfortunately there was no 3-HP titer in the broth of recombinant strains. In order to explore the regulatory mechanism of this pathway, cell-free synthetic enzymatic pathway was constructed. The low activity of acryloyl-CoA reductase, which catalyzed the reaction of the rate-limiting step, led to the absent of 3-HP.