Enhanced ethanol formation by Clostridium thermocellum via pyruvate decarboxylase.
Microb Cell Fact
; 16(1): 171, 2017 Oct 04.
Article
em En
| MEDLINE
| ID: mdl-28978312
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.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Piruvato Descarboxilase
/
Clostridium thermocellum
/
Etanol
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article