Enhanced ethanol formation by Clostridium thermocellum via pyruvate decarboxylase

Microbial Cell Factories

Research

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

[1] Bioenergy Science Center, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA;Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA;Dartmouth College, 03755, Hanover, NH, USA;Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, 03755, Hanover, NH, USA;Bioenergy Science Center, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA;

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

DOI  :  10.1186/s12934-017-0783-9

 received in 2017-06-19, accepted in 2017-09-26,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundPyruvate 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.ResultHere 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.ConclusionThe 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】

CC BY   
© The Author(s) 2017