title: Enhanced butanol fermentation using metabolically engineered Clostridium acetobutylicum with ex situ recovery of butanol.
abstract: In this study, metabolic target reactions for strain engineering were searched via intracellular coenzyme A (CoA) metabolite analysis. The metabolic reactions catalyzed by thiolase (AtoB) and aldehyde-alcohol dehydrogenase (AdhE1) were considered potential rate-limiting steps. In addition, CoA transferase (CtfAB) was highlighted as being important for the assimilation of organic acids, in order to achieve high butanol production. Based on this quantitative analysis, the BEKW_E1AB-atoB strain was constructed by overexpressing the thl (atoB), adhE1, and ctfAB genes in Clostridium acetobutylicum strain BEKW, which has the phosphotransacetylase (pta) and butyrate kinase (buk) genes knocked out. After 100h of continuous fermentation coupled with adsorptive ex situ butanol recovery, the concentrations found after considering desorption, yield, and productivity for the BEKW_E1AB-atoB strain were 55.7g/L, 0.38g/g, and 2.64g/L/h, respectively. The level of butanol production achieved (2.64g/L/h) represents the highest reported value obtained after adsorptive, long-term fermentation.
authors.affiliation: Department of Biotechnology, Graduate School, Korea University, Seoul 02841, South Korea.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Biotechnology, Graduate School, Korea University, Seoul 02841, South Korea.
authors.forename: Sooah
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Biotechnology, Graduate School, Korea University, Seoul 02841, South Korea.
authors.forename: Jung Yeon
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Environmental Analysis Division, Korea Apparel Testing & Research Institute, Anyang 14088, South Korea.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Cheong
authors.affiliation: Department of Biotechnology, Graduate School, Korea University, Seoul 02841, South Korea. Electronic address: khekim@korea.ac.kr.
authors.forename: Kyoung Heon
authors.initials: KH
authors.lastname: Kim
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D000440:Butanols / Q000378:metabolism*; D046969:Clostridium acetobutylicum / Q000378:metabolism*; D005285:Fermentation; D060847:Metabolic Engineering / Q000379:methods*
chemical_list: D000440:Butanols
keywords: Acetone-butanol-ethanol fermentation; Clostridium acetobutylicum; Coenzyme A; Intracellular metabolite analysis; Metabolic engineering