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Enhanced cellobiose fermentation by engineered Saccharomyces cerevisiae expressing a mutant cellodextrin facilitator and cellobiose phosphorylase.
- Source :
-
Journal of biotechnology [J Biotechnol] 2018 Jun 10; Vol. 275, pp. 53-59. Date of Electronic Publication: 2018 Apr 13. - Publication Year :
- 2018
-
Abstract
- To efficiently ferment intermediate cellodextrins released during cellulose hydrolysis, Saccharomyces cerevisiae has been engineered by introduction of a heterologous cellodextrin utilizing pathway consisting of a cellodextrin transporter and either an intracellular β-glucosidase or a cellobiose phosphorylase. Among two types of cellodextrin transporters, the passive facilitator CDT-2 has not enabled better cellobiose fermentation than the active transporter CDT-1, which suggests that the CDT-2 might be engineered to provide energetic benefits over the active transporter in cellobiose fermentation. We attempted to improve cellobiose transporting activity of CDT-2 through laboratory evolution. Nine rounds of a serial subculture of S. cerevisiae expressing CDT-2 and cellobiose phosphorylase on cellobiose led to the isolation of an evolved strain capable of fermenting cellobiose to ethanol 10-fold faster than the original strain. After sequence analysis of the isolated CDT-2, a single point mutation on CDT-2 (N306I) was revealed to be responsible for enhanced cellobiose fermentation. Also, the engineered strain expressing the mutant CDT-2 with cellobiose phosphorylase showed a higher ethanol yield than the engineered strain expressing CDT-1 and intracellular β-glucosidase under anaerobic conditions, suggesting that CDT-2 coupled with cellobiose phosphorylase may be better choices for efficient production of cellulosic ethanol with the engineered yeast.<br /> (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Subjects :
- Cellulose analogs & derivatives
Cellulose metabolism
Dextrins metabolism
Fermentation
Glucosyltransferases metabolism
Membrane Transport Proteins metabolism
Metabolic Engineering
Recombinant Proteins
Saccharomyces cerevisiae genetics
Saccharomyces cerevisiae metabolism
Cellobiose chemistry
Glucosyltransferases genetics
Membrane Transport Proteins genetics
Saccharomyces cerevisiae growth & development
Subjects
Details
- Language :
- English
- ISSN :
- 1873-4863
- Volume :
- 275
- Database :
- MEDLINE
- Journal :
- Journal of biotechnology
- Publication Type :
- Academic Journal
- Accession number :
- 29660472
- Full Text :
- https://doi.org/10.1016/j.jbiotec.2018.04.008