title: Engineering Clostridium acetobutylicum with a histidine kinase knockout for enhanced n-butanol tolerance and production.
abstract: Clostridium acetobutylicum JB200, a mutant strain of C. acetobutylicum ATCC 55025 obtained through strain evolution in a fibrous bed bioreactor, had high butanol tolerance and produced up to ~21 g/L butanol from glucose in batch fermentation, an improvement of ~67 % over the parental strain (~12.6 g/L). Comparative genomic analysis revealed a single-base deletion in the cac3319 gene leading to C-terminal truncation in its encoding histidine kinase (HK) in JB200. To study the effects of cac3319 mutation on cell growth and fermentation, the cac3319 gene in ATCC 55025 was disrupted using the ClosTron group II intron-based gene inactivation system. Compared to ATCC 55025, the cac3319 HK knockout mutant, HKKO, produced 44.4 % more butanol (18.2 ± 1.3 vs. 12.6 ± 0.2 g/L) with a 90 % higher productivity (0.38 ± 0.03 vs. 0.20 ± 0.02 g/L h) due to increased butanol tolerance, confirming, for the first time, that cac3319 plays an important role in regulating solvent production and tolerance in C. acetobutylicum. This work also provides a novel metabolic engineering strategy for generating high-butanol-tolerant and high-butanol-producing strains for industrial applications.
authors.affiliation: William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W. 19th Ave, Columbus, OH, 43210, USA.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Xu
authors.forename: Jingbo
authors.initials: J
authors.lastname: Zhao
authors.forename: Le
authors.initials: L
authors.lastname: Yu
authors.forename: I-Ching
authors.initials: IC
authors.lastname: Tang
authors.forename: Chuang
authors.initials: C
authors.lastname: Xue
authors.forename: Shang-Tian
authors.initials: ST
authors.lastname: Yang
mesh_terms: D020001:1-Butanol / Q000378:metabolism*; D003001:Cloning, Molecular; D046969:Clostridium acetobutylicum / Q000235:genetics* / Q000378:metabolism; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D000071677:Histidine Kinase; D007218:Industrial Microbiology; D060847:Metabolic Engineering / Q000379:methods*; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D012997:Solvents / Q000737:chemistry
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D012997:Solvents; D020001:1-Butanol; D011494:Protein Kinases; D000071677:Histidine Kinase; D005947:Glucose