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论文类型： 期刊论文

发表时间： 2015-01-01

发表刊物： APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

收录刊物： SCIE、EI、Scopus

卷号： 99

期号： 2

页面范围： 1011-1022

ISSN号： 0175-7598

关键字： ABE fermentation; Butanol tolerance; C. acetobutylicum; Histidine kinase; Gene knockout; Metabolic engineering

摘要： 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 similar to 21 g/L butanol from glucose in batch fermentation, an improvement of similar to 67 % over the parental strain (similar to 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.