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Adaptation of Scheffersomyces stipitis to hardwood spent sulfite liquor by evolutionary engineering

Pereira, Susana R.; Sanchez Nogue, Violeta LU ; Frazao, Cludio J. R.; Serafim, Luisa S.; Gorwa-Grauslund, Marie-Francoise LU and Xavier, Ana M. R. B. (2015) In Biotechnology for Biofuels 8.
Abstract
Background: Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol. Results: A continuous reactor with gradually increasing HSSL concentrations, from 20% to 60% (v/v), was operated for 382 generations. From the final obtained population (POP), a stable clone (C-4) was isolated and... (More)
Background: Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol. Results: A continuous reactor with gradually increasing HSSL concentrations, from 20% to 60% (v/v), was operated for 382 generations. From the final obtained population (POP), a stable clone (C-4) was isolated and characterized in 60% undetoxified HSSL. C-4 isolate was then compared with both the parental strain (PAR) and POP. Both POP and C-4 were able to grow in 60% undetoxified HSSL, with a higher capability to withstand HSSL inhibitors than PAR. Higher substrate uptake rates, 7% higher ethanol efficiency and improved ethanol yield were obtained using C-4. Conclusion: S. stipitis was successfully adapted to 60% (v/v) undetoxified eucalyptus HSSL. A stable isolate, C-4, with an improved performance in undetoxified HSSL compared to PAR was successfully obtained from POP. Owing to its improved tolerance to inhibitors, C-4 may represent a major advantage for the production of bioethanol using HSSL as substrate. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Hardwood spent sulfite liquor (HSSL), Scheffersomyces stipitis, Lignocellulosic inhibitors, Evolutionary engineering, Bioethanol
in
Biotechnology for Biofuels
volume
8
publisher
BioMed Central
external identifiers
  • wos:000351901900001
  • pmid:25829945
  • scopus:84959858490
ISSN
1754-6834
DOI
10.1186/s13068-015-0234-y
language
English
LU publication?
yes
id
fa584036-ca89-4540-8659-c0ea5d996a7f (old id 5277888)
date added to LUP
2015-04-24 09:53:02
date last changed
2017-06-18 04:10:10
@article{fa584036-ca89-4540-8659-c0ea5d996a7f,
  abstract     = {Background: Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol. Results: A continuous reactor with gradually increasing HSSL concentrations, from 20% to 60% (v/v), was operated for 382 generations. From the final obtained population (POP), a stable clone (C-4) was isolated and characterized in 60% undetoxified HSSL. C-4 isolate was then compared with both the parental strain (PAR) and POP. Both POP and C-4 were able to grow in 60% undetoxified HSSL, with a higher capability to withstand HSSL inhibitors than PAR. Higher substrate uptake rates, 7% higher ethanol efficiency and improved ethanol yield were obtained using C-4. Conclusion: S. stipitis was successfully adapted to 60% (v/v) undetoxified eucalyptus HSSL. A stable isolate, C-4, with an improved performance in undetoxified HSSL compared to PAR was successfully obtained from POP. Owing to its improved tolerance to inhibitors, C-4 may represent a major advantage for the production of bioethanol using HSSL as substrate.},
  articleno    = {50},
  author       = {Pereira, Susana R. and Sanchez Nogue, Violeta and Frazao, Cludio J. R. and Serafim, Luisa S. and Gorwa-Grauslund, Marie-Francoise and Xavier, Ana M. R. B.},
  issn         = {1754-6834},
  keyword      = {Hardwood spent sulfite liquor (HSSL),Scheffersomyces stipitis,Lignocellulosic inhibitors,Evolutionary engineering,Bioethanol},
  language     = {eng},
  publisher    = {BioMed Central},
  series       = {Biotechnology for Biofuels},
  title        = {Adaptation of Scheffersomyces stipitis to hardwood spent sulfite liquor by evolutionary engineering},
  url          = {http://dx.doi.org/10.1186/s13068-015-0234-y},
  volume       = {8},
  year         = {2015},
}