Enhanced ethanol formation by Clostridium thermocellum via pyruvate decarboxylase

Microbial Cell Factories

Jason T. Bouvier¹  Adam M. Guss¹  Skyler J. Perot²  Daniel G. Olson³  Shuen Hon³  Xiaoyu Liang³  Liang Tian³  Lee R. Lynd³  Jilai Zhou³ 

[1] Bioenergy Science Center, Oak Ridge National Laboratory;Dartmouth College;Thayer School of Engineering, Dartmouth College;

关键词: Consolidated bioprocessing;    Clostridium thermocellum;    Cellulosic ethanol;    Pyruvate decarboxylase;    Alcohol dehydrogenase;   

DOI  :  10.1186/s12934-017-0783-9

来源: DOAJ

【 摘 要 】

Abstract Background Pyruvate decarboxylase (PDC) is a well-known pathway for ethanol production, but has not been demonstrated for high titer ethanol production at temperatures above 50 °C. Result Here we examined the thermostability of eight PDCs. The purified bacterial enzymes retained 20% of activity after incubation for 30 min at 55 °C. Expression of these PDC genes, except the one from Zymomonas mobilis, improved ethanol production by Clostridium thermocellum. Ethanol production was further improved by expression of the heterologous alcohol dehydrogenase gene adhA from Thermoanaerobacterium saccharolyticum. Conclusion The best PDC enzyme was from Acetobactor pasteurianus. A strain of C. thermocellum expressing the pdc gene from A. pasteurianus and the adhA gene from T. saccharolyticum was able to produce 21.3 g/L ethanol from 60 g/L cellulose, which is 70% of the theoretical maximum yield.

【 授权许可】

Unknown