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Adaptive evolution of an industrial strain of Saccharomyces cerevisiae for combined tolerance to inhibitors and temperature

Wallace, Valeria LU and Gorwa-Grauslund, Marie-Francoise LU (2013) In Biotechnology for Biofuels 6.
Abstract
Introduction: Development of industrial yeast strains with high tolerance towards the inhibitors released during biomass pretreatment is critical for bioethanol production. Combining this trait with increased thermotolerance would result in a more efficient production via Simultaneous Saccharification and Fermentation (SSF) as well as reduced cooling costs. The aim of the present work was to develop a yeast strain combining these traits. Results: Using a long-term adaptation strategy a stable Saccharomyces cerevisiae isolate (ISO12) was evolved from the industrial strain Ethanol Red (ER). ISO12, contrary to the parental strain, is capable of growing and fermenting the liquid fraction of non-detoxified spruce hydrolysate at 39 degrees C... (More)
Introduction: Development of industrial yeast strains with high tolerance towards the inhibitors released during biomass pretreatment is critical for bioethanol production. Combining this trait with increased thermotolerance would result in a more efficient production via Simultaneous Saccharification and Fermentation (SSF) as well as reduced cooling costs. The aim of the present work was to develop a yeast strain combining these traits. Results: Using a long-term adaptation strategy a stable Saccharomyces cerevisiae isolate (ISO12) was evolved from the industrial strain Ethanol Red (ER). ISO12, contrary to the parental strain, is capable of growing and fermenting the liquid fraction of non-detoxified spruce hydrolysate at 39 degrees C with an ethanol yield of 0.38 g ethanol. g hexoses(-1). In contrast with previous studies, the superior phenotype of ISO12 does not rely on higher reductase activities for furaldehyde inhibitor conversion, but rather on a higher thermotolerance. ISO12 shows a higher capacity to ferment hydrolysate at 39 degrees C and higher viability during heat- shock at 52 degrees C than ER. In the absence of inhibitors, however, both ER and ISO12 displayed similar growth phenotype at 39 degrees C. Conclusions: The evolved isolate ISO12 shows a superior phenotype than the parental strain ER when both stresses, temperature and inhibition by hydrolysate-derived compounds, are applied together. The results suggest that the presence of inhibitors depress the maximum temperature permissible for growth to a value below 39 degrees C. As a result of the adaptation process and acquired improved thermotolerance, ISO12 is able to overcome this synergistic effect. Robust strains, such as ISO12, are interesting candidates for second generation ethanol production by SSF, as well as in tropical countries where fermentations at higher temperature can positively impact the production costs. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Saccharomyces cerevisiae, Evolution, Thermotolerance, Hydrolysate, Inhibitors, Ethanol
in
Biotechnology for Biofuels
volume
6
publisher
BioMed Central
external identifiers
  • wos:000326652600001
  • scopus:84885551317
ISSN
1754-6834
DOI
10.1186/1754-6834-6-151
language
English
LU publication?
yes
id
9a85f898-b4c6-418f-a6f4-0e0804189f39 (old id 4208349)
date added to LUP
2014-01-07 12:55:06
date last changed
2019-03-17 04:08:23
@article{9a85f898-b4c6-418f-a6f4-0e0804189f39,
  abstract     = {Introduction: Development of industrial yeast strains with high tolerance towards the inhibitors released during biomass pretreatment is critical for bioethanol production. Combining this trait with increased thermotolerance would result in a more efficient production via Simultaneous Saccharification and Fermentation (SSF) as well as reduced cooling costs. The aim of the present work was to develop a yeast strain combining these traits. Results: Using a long-term adaptation strategy a stable Saccharomyces cerevisiae isolate (ISO12) was evolved from the industrial strain Ethanol Red (ER). ISO12, contrary to the parental strain, is capable of growing and fermenting the liquid fraction of non-detoxified spruce hydrolysate at 39 degrees C with an ethanol yield of 0.38 g ethanol. g hexoses(-1). In contrast with previous studies, the superior phenotype of ISO12 does not rely on higher reductase activities for furaldehyde inhibitor conversion, but rather on a higher thermotolerance. ISO12 shows a higher capacity to ferment hydrolysate at 39 degrees C and higher viability during heat- shock at 52 degrees C than ER. In the absence of inhibitors, however, both ER and ISO12 displayed similar growth phenotype at 39 degrees C. Conclusions: The evolved isolate ISO12 shows a superior phenotype than the parental strain ER when both stresses, temperature and inhibition by hydrolysate-derived compounds, are applied together. The results suggest that the presence of inhibitors depress the maximum temperature permissible for growth to a value below 39 degrees C. As a result of the adaptation process and acquired improved thermotolerance, ISO12 is able to overcome this synergistic effect. Robust strains, such as ISO12, are interesting candidates for second generation ethanol production by SSF, as well as in tropical countries where fermentations at higher temperature can positively impact the production costs.},
  articleno    = {151},
  author       = {Wallace, Valeria and Gorwa-Grauslund, Marie-Francoise},
  issn         = {1754-6834},
  keyword      = {Saccharomyces cerevisiae,Evolution,Thermotolerance,Hydrolysate,Inhibitors,Ethanol},
  language     = {eng},
  publisher    = {BioMed Central},
  series       = {Biotechnology for Biofuels},
  title        = {Adaptive evolution of an industrial strain of Saccharomyces cerevisiae for combined tolerance to inhibitors and temperature},
  url          = {http://dx.doi.org/10.1186/1754-6834-6-151},
  volume       = {6},
  year         = {2013},
}