Enhanced butanol production in Clostridium acetobutylicum by manipulating metabolic pathway genes

• Published in: Process biochemistry (1991) Vol. 114; pp. 134 - 138
• Main Authors: Du, Guangqing, Wu, Youduo, Kang, Wei, Xu, Yongping, Li, Shuying, Xue, Chuang
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.03.2022; Elsevier BV
• Subjects: Acetaldehyde; Acetaldehyde/alcohol dehydrogenase; Acetoacetate decarboxylase; Acetone; Alcohol dehydrogenase; Biosynthesis; Butanol; Clostridium acetobutylicum; Ethanol; Fermentation; Genes; Histidine; Histidine kinase; Kinases; Metabolic pathways; Mutants; Productivity; Clostridium acetobutylicum; Butanol; Acetaldehyde/alcohol dehydrogenase; Acetoacetate decarboxylase
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2022.01.021

[Display omitted] •A robust strain with enhanced butanol production was metabolically engineered.•The butanol/ABE ratio increased from 63.2 %–87.6 % by knocking out adc gene.•The knockout of adc gene limited butanol production to ∼11 g/L.•Maximum butanol titer of 19.7 g/L was obtained by overexpressing adhE2 gene. Biobutanol is naturally produced by solventogenic clostridia during acetone-butanol-ethanol (ABE) fermentation, which is hampered by low butanol titer, yield and productivity. Here, Clostridium acetobutylicum ATCC 55025 and its robust mutant HKKO with histidine kinase genes cac3319/cac0323 knockout were metabolically engineered to eliminate acetone formation and improve butanol production. By knocking out acetoacetate decarboxylase gene adc in ATCC 55025 and HKKO, the acetone titer decreased to 0.1 g/L and the butanol/ABE ratio increased by 39.0 % and 40.9 %, respectively. However, the butanol production was limited to ∼11 g/L. To improve butanol production, an alternative strategy was used by overexpressing acetaldehyde/alcohol dehydrogenase gene adhE2 in HKKO, and the mutant produced butanol of 19.7 g/L than that of 18.2 g/L from HKKO with high butanol productivity of 0.41 g/L/h and yield of 0.26 g/g. This study provides novel insights into the roles of adc and adhE2 on butanol biosynthesis and generates a hyper-butanol-producing strain.