Production of 1,3-propanediol from glycerol by engineered Escherichia coli using a novel co- expression vector

Abstract

1,3-Propanediol (1,3-PD) has versatile applications in polymers, cosmetics, foods and medicines. In order to consolidate the functions of glycerol dehydratase genedhaB and 1,3-propanediol oxidoreductase gene dhaT and produce 1,3-PD from glycerol, the genes dhaB and dhaT from Klebsiella pneumoniae were inserted into a co-expression vector pACYCDuet-1 synchronously and the recombinant strain E. coli/pACYCDuet-dhaB-dhaT was obtained. Both enzymes were functionally co-expressed in E. coli at the presence of the selective pressure and the addition of the IPTG. The specific enzyme activity of DHAB and DHAT were 8.3 and 6.2 U/mg, respectively. When cultivated at 37°C for 30 h, the recombinant microorganisms produced 1,3-PD of 11.3 g with the consumption of 40 g glycerol per liter. The production of 1,3-PD by the strain E. coli/pACYCDuet-dhaB-dhaT was about 13-fold higher than the recombinant E. coli harboring the gene dhaB. Key words: 1,3-propanediol, Klebsiella pneumoniae, co-expression system, T7RNA polymerase promoter.