title: High Production of 2,3-Butanediol (2,3-BD) by Raoultella ornithinolytica B6 via Optimizing Fermentation Conditions and Overexpressing 2,3-BD Synthesis Genes.
abstract: Biological production of 2,3-butandiol (2,3-BD) has received great attention as an alternative to the petroleum-based 2,3-BD production. In this study, a high production of 2,3-BD in fed-batch fermentation was investigated with a newly isolated bacterium designated as Raoultella ornithinolytica B6. The isolate produced 2,3-BD as the main product using hexoses (glucose, galactose, and fructose), pentose (xylose) and disaccharide (sucrose). The effects of temperature, pH-control schemes, and agitation speeds on 2,3-BD production were explored to optimize the fermentation conditions. Notably, cell growth and 2,3-BD production by R. ornithinolytica B6 were higher at 25°C than at 30°C. When three pH control schemes (no pH control, pH control at 7, and pH control at 5.5 after the pH was decreased to 5.5 during fermentation) were tested, the best 2,3-BD titer and productivity along with reduced by-product formation were achieved with pH control at 5.5. Among different agitation speeds (300, 400, and 500 rpm), the optimum agitation speed was 400 rpm with 2,3-BD titer of 68.27 g/L, but acetic acid was accumulated up to 23.32 g/L. Further enhancement of the 2,3-BD titer (112.19 g/L), yield (0.38 g/g), and productivity (1.35 g/L/h) as well as a significant reduction of acetic acid accumulation (9.71 g/L) was achieved by the overexpression of homologous budABC genes, the 2,3-BD-synthesis genes involved in the conversion of pyruvate to 2,3-BD. This is the first report presenting a high 2,3-BD production by R.ornithinolytica which has attracted little attention with respect to 2,3-BD production, extending the microbial spectrum of 2,3-BD producers.
authors.affiliation: Interdisciplinary program in agriculture biotechnology, College of Agriculture and Life Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.|Clean Energy Center, Korea Institute of Science and Technology (KIST), Seongbuk-gu, Seoul, 136-791, Republic of Korea.
authors.forename: Taeyeon
authors.initials: T
authors.lastname: Kim
authors.affiliation: Korea C1 gas refinery R&D center, Sogang University, Seoul, 121-742, Republic of Korea.
authors.forename: Sukhyeong
authors.initials: S
authors.lastname: Cho
authors.affiliation: Clean Energy Center, Korea Institute of Science and Technology (KIST), Seongbuk-gu, Seoul, 136-791, Republic of Korea.|Clean Energy and Chemical Engineering, Korea University of Science and Technology, Daejeon, Republic of Korea.
authors.forename: Sun-Mi
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, 16419, South Korea.
authors.forename: Han Min
authors.initials: HM
authors.lastname: Woo
authors.affiliation: Korea C1 gas refinery R&D center, Sogang University, Seoul, 121-742, Republic of Korea.|Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 121-742, Republic of Korea.
authors.forename: Jinwon
authors.initials: J
authors.lastname: Lee
authors.affiliation: Clean Energy Center, Korea Institute of Science and Technology (KIST), Seongbuk-gu, Seoul, 136-791, Republic of Korea.|Clean Energy and Chemical Engineering, Korea University of Science and Technology, Daejeon, Republic of Korea.
authors.forename: Youngsoon
authors.identifier: http://orcid.org/0000-0003-1695-1874
authors.initials: Y
authors.lastname: Um
authors.affiliation: Interdisciplinary program in agriculture biotechnology, College of Agriculture and Life Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.|Department of Agricultural Biotechnology and Center for Food and Bioconvergence, Seoul National University, Seoul, 151-742, Republic of Korea.
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Seo
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D061249:Batch Cell Culture Techniques / Q000379:methods*; D002072:Butylene Glycols / Q000378:metabolism*; D004755:Enterobacteriaceae / Q000201:enzymology / Q000254:growth & development*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D002072:Butylene Glycols; C026978:2,3-butylene glycol