Ma Chao, Ou Jianfa, Xu Ningning, Fierst Janna L, Yang Shang-Tian, Liu Xiaoguang
Department of Chemical and Biological Engineering, The University of Alabama, 245 7th Avenue, Tuscaloosa, AL 35401, USA.
Department of Biological Science, The University of Alabama, 300 Hackberry Lane, Tuscaloosa, AL 35487, USA.
Bioengineering (Basel). 2015 Dec 24;3(1):2. doi: 10.3390/bioengineering3010002.
Biobutanol is a sustainable green biofuel that can substitute for gasoline. Carbon flux has been redistributed in 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-- was constructed by introducing heterologous formate dehydrogenase () and bifunctional aldehyde/alcohol dehydrogenase () simultaneously into wild-type . The mutant evaluation indicated that the -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--, which was 3.88-fold higher than that produced by the control mutant CTC-. This study demonstrated that the redox engineering in could greatly increase butanol production.
生物丁醇是一种可持续的绿色生物燃料，可替代汽油。通过代谢细胞工程在[具体微生物名称未给出]中重新分配了碳通量以生产生物丁醇。然而，还原力的缺乏阻碍了丁醇产量的进一步提高。本研究的目的是通过重新平衡氧化还原反应来提高丁醇产量。首先，通过将异源甲酸脱氢酶（[具体名称未给出]）和双功能醛/醇脱氢酶（[具体名称未给出]）同时引入野生型[具体微生物名称未给出]中，构建了代谢工程突变体CTC--。突变体评估表明，由[具体酶名称未给出]催化的产生NADH的途径在血清瓶中使丁醇滴度提高了2.15倍，在生物反应器中提高了2.72倍。其次，确定了可以改变代谢通量以提高丁酸盐或丁醇产量的培养基补充物，包括钒酸盐、乙酰胺、甲酸钠、维生素B12和水合甲基紫精。最后，使用突变体CTC--通过游离细胞发酵从葡萄糖中产生了12.34 g/L的丁醇，这比对照突变体CTC-产生的丁醇高3.88倍。本研究表明，[具体微生物名称未给出]中的氧化还原工程可大大提高丁醇产量。
