Rebalancing Redox to Improve Biobutanol Production by Clostridium tyrobutyricum

Bioengineering

Chao Ma¹  Jianfa Ou¹  Ningning Xu¹  Janna L. Fierst³  Shang-Tian Yang²  Xiaoguang (Margaret) Liu¹  Mark Blenner⁴ 

[1] Department of Chemical and Biological Engineering, The University of Alabama, 245 7th Avenue, Tuscaloosa, AL 35401, USA;Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA;Department of Biological Science, The University of Alabama, 300 Hackberry Lane, Tuscaloosa, AL 35487, USA;;Department of Chemical and Biological Engineering, The University of Alabama, 245 7th Avenue, Tuscaloosa, AL 35401, USA

关键词: Clostridium tyrobutyricum;    butanol production;    redox engineering;    metabolic cell engineering;    metabolic shift;   

DOI  :  10.3390/bioengineering3010002

来源: mdpi

【 摘 要 】

Biobutanol is a sustainable green biofuel that can substitute for gasoline. Carbon flux has been redistributed in Clostridium tyrobutyricum via metabolic cell engineering to produce biobutanol. However, the lack of reducing power hampered the further improvement of butanol production. The objective of this study was to improve butanol production by rebalancing redox. Firstly, a metabolically-engineered mutant CTC-fdh-adhE2 was constructed by introducing heterologous formate dehydrogenase (fdh) and bifunctional aldehyde/alcohol dehydrogenase (adhE2) simultaneously into wild-type C. tyrobutyricum. The mutant evaluation indicated that the fdh-catalyzed NADH-producing pathway improved butanol titer by 2.15-fold in the serum bottle and 2.72-fold in the bioreactor. Secondly, the medium supplements that could shift metabolic flux to improve the production of butyrate or butanol were identified, including vanadate, acetamide, sodium formate, vitamin B12 and methyl viologen hydrate. Finally, the free-cell fermentation produced 12.34 g/L of butanol from glucose using the mutant CTC-fdh-adhE2, which was 3.88-fold higher than that produced by the control mutant CTC-adhE2. This study demonstrated that the redox engineering in C. tyrobutyricum could greatly increase butanol production.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.