title: Redistribution of carbon flux toward 2,3-butanediol production in Klebsiella pneumoniae by metabolic engineering.
abstract: Klebsiella pneumoniae KCTC2242 has high potential in the production of a high-value chemical, 2,3-butanediol (2,3-BDO). However, accumulation of metabolites such as lactate during cell growth prevent large-scale production of 2,3-BDO. Consequently, we engineered K. pneumoniae to redistribute its carbon flux toward 2,3-BDO production. The ldhA gene deletion and gene overexpression (budA and budB) were conducted to block a pathway that competitively consumes reduced nicotinamide adenine dinucleotide and to redirect carbon flux toward 2,3-BDO biosynthesis, respectively. These steps allowed efficient glucose conversion to 2,3-BDO under slightly acidic conditions (pH 5.5). The engineered strain SGSB105 showed a 40% increase in 2,3-BDO production from glucose compared with that of the host strain, SGSB100. Genes closely related to 2,3-BDO biosynthesis were observed at the gene transcription level by cultivating the SGSB100, SGSB103, SGSB104, and SGSB105 strains under identical growth conditions. Transcription levels for budA, budB, and budC increased approximately 10% during the log phase of cell growth relative to that of SGSB100. Transcription levels of 2,3-BDO genes in SGSB105 remained high during the log and stationary phases. Thus, the carbon flux was redirected toward 2,3-BDO production. Data on batch culture and gene transcription provide insight into improving the metabolic network for 2,3-BDO biosynthesis for industrial applications.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea.
authors.forename: Borim
authors.initials: B
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea.
authors.forename: Soojin
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea.
authors.forename: Daun
authors.initials: D
authors.lastname: Jeong
authors.affiliation: Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea.
authors.forename: Jeongmo
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea.
authors.forename: Min-Kyu
authors.initials: MK
authors.lastname: Oh
authors.affiliation: Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea.
authors.forename: Jinwon
authors.initials: J
authors.lastname: Lee
mesh_terms: D061249:Batch Cell Culture Techniques; D002072:Butylene Glycols / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D005285:Fermentation; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000235:genetics; D060847:Metabolic Engineering; D009154:Mutation; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D002072:Butylene Glycols; C026978:2,3-butylene glycol; D002244:Carbon; D007770:L-Lactate Dehydrogenase