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A mutated xylose reductase increases bioethanol production more than a glucose/xylose facilitator in simultaneous fermentation and co-fermentation of wheat straw.

Olofsson, Kim LU ; Runquist, David LU ; Hahn-Hägerdal, Bärbel LU and Lidén, Gunnar LU (2011) In AMB Express 1(1).
Abstract
ABSTRACT: Genetically engineered Saccharomyces cerevisiae strains are able to ferment xylose present in lignocellulosic biomass. However, better xylose fermenting strains are required to reach complete xylose uptake in simultaneous saccharification and co-fermentation (SSCF) of lignocellulosic hydrolyzates. In the current study, haploid Saccharomyces cerevisiae strains expressing a heterologous xylose pathway including either the native xylose reductase (XR) from P. stipitis, a mutated variant of XR (mXR) with altered co-factor preference, a glucose/xylose facilitator (Gxf1) from Candida intermedia or both mXR and Gxf1 were assessed in SSCF of acid-pretreated non-detoxified wheat straw. The xylose conversion in SSCF was doubled with the S.... (More)
ABSTRACT: Genetically engineered Saccharomyces cerevisiae strains are able to ferment xylose present in lignocellulosic biomass. However, better xylose fermenting strains are required to reach complete xylose uptake in simultaneous saccharification and co-fermentation (SSCF) of lignocellulosic hydrolyzates. In the current study, haploid Saccharomyces cerevisiae strains expressing a heterologous xylose pathway including either the native xylose reductase (XR) from P. stipitis, a mutated variant of XR (mXR) with altered co-factor preference, a glucose/xylose facilitator (Gxf1) from Candida intermedia or both mXR and Gxf1 were assessed in SSCF of acid-pretreated non-detoxified wheat straw. The xylose conversion in SSCF was doubled with the S. cerevisiae strain expressing mXR compared to the isogenic strain expressing the native XR, converting 76% and 38%, respectively. The xylitol yield was less than half using mXR in comparison with the native variant. As a result of this, the ethanol yield increased from 0.33 to 0.39 g g-1 when the native XR was replaced by mXR. In contrast, the expression of Gxf1 only slightly increased the xylose uptake, and did not increase the ethanol production. The results suggest that ethanolic xylose fermentation under SSCF conditions is controlled primarily by the XR activity and to a much lesser extent by xylose transport. (Less)
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organization
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Contribution to journal
publication status
published
subject
in
AMB Express
volume
1
issue
1
publisher
Springer Open
external identifiers
  • pmid:21906329
  • scopus:84855362753
ISSN
2191-0855
DOI
10.1186/2191-0855-1-4
language
English
LU publication?
yes
id
daa5caab-103a-47eb-8eb7-0d3e4b1d2867 (old id 2169016)
date added to LUP
2011-09-30 09:34:34
date last changed
2017-01-01 06:18:12
@article{daa5caab-103a-47eb-8eb7-0d3e4b1d2867,
  abstract     = {ABSTRACT: Genetically engineered Saccharomyces cerevisiae strains are able to ferment xylose present in lignocellulosic biomass. However, better xylose fermenting strains are required to reach complete xylose uptake in simultaneous saccharification and co-fermentation (SSCF) of lignocellulosic hydrolyzates. In the current study, haploid Saccharomyces cerevisiae strains expressing a heterologous xylose pathway including either the native xylose reductase (XR) from P. stipitis, a mutated variant of XR (mXR) with altered co-factor preference, a glucose/xylose facilitator (Gxf1) from Candida intermedia or both mXR and Gxf1 were assessed in SSCF of acid-pretreated non-detoxified wheat straw. The xylose conversion in SSCF was doubled with the S. cerevisiae strain expressing mXR compared to the isogenic strain expressing the native XR, converting 76% and 38%, respectively. The xylitol yield was less than half using mXR in comparison with the native variant. As a result of this, the ethanol yield increased from 0.33 to 0.39 g g-1 when the native XR was replaced by mXR. In contrast, the expression of Gxf1 only slightly increased the xylose uptake, and did not increase the ethanol production. The results suggest that ethanolic xylose fermentation under SSCF conditions is controlled primarily by the XR activity and to a much lesser extent by xylose transport.},
  articleno    = {4},
  author       = {Olofsson, Kim and Runquist, David and Hahn-Hägerdal, Bärbel and Lidén, Gunnar},
  issn         = {2191-0855},
  language     = {eng},
  number       = {1},
  publisher    = {Springer Open},
  series       = {AMB Express},
  title        = {A mutated xylose reductase increases bioethanol production more than a glucose/xylose facilitator in simultaneous fermentation and co-fermentation of wheat straw.},
  url          = {http://dx.doi.org/10.1186/2191-0855-1-4},
  volume       = {1},
  year         = {2011},
}