title: Improved 1,3-propanediol production by engineering the 2,3-butanediol and formic acid pathways in integrative recombinant Klebsiella pneumoniae.
abstract: In the biotechnological process, insufficient cofactor NADH and multiple by-products restrain the final titer of 1,3-propanediol (1,3-PD). In this study, 1,3-PD production was improved by engineering the 2,3-butanediol (2,3-BD) and formic acid pathways in integrative recombinant Klebsiella pneumoniae. The formation of 2,3-BD is catalysed by acetoin reductase (AR). An inactivation mutation of the AR in K. pneumoniae CF was generated by insertion of a formate dehydrogenase gene. Inactivation of AR and expression of formate dehydrogenase reduced 2,3-BD formation and improved 1,3-PD production. Fermentation results revealed that intracellular metabolic flux was redistributed pronouncedly. The yield of 1,3-PD reached 0.74 mol/mol glycerol in flask fermentation, which is higher than the theoretical yield. In 5 L fed-batch fermentation, the final titer and 1,3-PD yield of the K. pneumoniae CF strain reached 72.2 g/L and 0.569 mol/mol, respectively, which were 15.9% and 21.7% higher than those of the wild-type strain. The titers of 2,3-BD and formic acid decreased by 52.2% and 73.4%, respectively. By decreasing the concentration of all nonvolatile by-products and by increasing the availability of NADH, this study demonstrates an important strategy in the metabolic engineering of 1,3-PD production by integrative recombinant hosts.
authors.affiliation: Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.forename: Guoqing
authors.initials: G
authors.lastname: Wang
authors.forename: Tianwei
authors.initials: T
authors.lastname: Tan
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D002072:Butylene Glycols / Q000378:metabolism*; D005560:Formate Dehydrogenases / Q000235:genetics* / Q000378:metabolism; D005561:Formates / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing; D005798:Genes, Bacterial; D005800:Genes, Fungal; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000378:metabolism*; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D016254:Mutagenesis, Insertional; D009243:NAD / Q000378:metabolism*; D010843:Pichia / Q000201:enzymology / Q000235:genetics; D011409:Propylene Glycols / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D002072:Butylene Glycols; D005561:Formates; D005656:Fungal Proteins; D011409:Propylene Glycols; D011994:Recombinant Proteins; D009243:NAD; C026978:2,3-butylene glycol; C041787:1,3-propanediol; D000429:Alcohol Oxidoreductases; C019801:butanediol dehydrogenase; D005560:Formate Dehydrogenases
keywords: 1,3-Propanediol; 2,3-Butanediol; Formate dehydrogenase; Formic acid; Integrative recombinant; NADH regeneration