Saccharomyces cerevisiae strain comparison in glucose-xylose fermentations on defined substrates and in high-gravity SSCF: Convergence in strain performance despite differences in genetic and evolutionary engineering history

Vera Novy, Ruifei Wang, Johan O. Westman, Carl Johan Franzén, Bernd Nidetzky

Publikation: Beitrag in einer FachzeitschriftReview eines Fachbereichs (Review article)ForschungBegutachtung

Abstract

Background: The most advanced strains of xylose-fermenting Saccharomyces cerevisiae still utilize xylose far less efficiently than glucose, despite the extensive metabolic and evolutionary engineering applied in their development. Systematic comparison of strains across literature is difficult due to widely varying conditions used for determining key physiological parameters. Here, we evaluate an industrial and a laboratory S. cerevisiae strain, which has the assimilation of xylose via xylitol in common, but differ fundamentally in the history of their adaptive laboratory evolution development, and in the cofactor specificity of the xylose reductase (XR) and xylitol dehydrogenase (XDH). Results: In xylose and mixed glucose-xylose shaken bottle fermentations, with and without addition of inhibitor-rich wheat straw hydrolyzate, the specific xylose uptake rate of KE6-12.A (0.27-1.08 g g CDW -1 h-1) was 1.1 to twofold higher than that of IBB10B05 (0.10-0.82 g g CDW -1 h-1). KE6-12.A further showed a 1.1 to ninefold higher glycerol yield (0.08-0.15 g g-1) than IBB10B05 (0.01-0.09 g g-1). However, the ethanol yield (0.30-0.40 g g-1), xylitol yield (0.08-0.26 g g-1), and maximum specific growth rate (0.04-0.27 h-1) were in close range for both strains. The robustness of flocculating variants of KE6-12.A (KE-Flow) and IBB10B05 (B-Flow) was analyzed in high-gravity simultaneous saccharification and co-fermentation. As in shaken bottles, KE-Flow showed faster xylose conversion and higher glycerol formation than B-Flow, but final ethanol titres (61 g L-1) and cell viability were again comparable for both strains. Conclusions: Individual specific traits, elicited by the engineering strategy, can affect global physiological parameters of S. cerevisiae in different and, sometimes, unpredictable ways. The industrial strain background and prolonged evolution history in KE6-12.A improved the specific xylose uptake rate more substantially than the superior XR, XDH, and xylulokinase activities were able to elicit in IBB10B05. Use of an engineered XR/XDH pathway in IBB10B05 resulted in a lower glycerol rather than a lower xylitol yield. However, the strain development programs were remarkably convergent in terms of the achieved overall strain performance. This highlights the importance of comparative strain evaluation to advance the engineering strategies for next-generation S. cerevisiae strain development.

Originalspracheenglisch
Aufsatznummer205
FachzeitschriftBiotechnology for Biofuels
Jahrgang10
Ausgabenummer1
DOIs
PublikationsstatusVeröffentlicht - 4 Sep 2017

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Hypergravity
Xylose
Genetic Engineering
Yeast
Fermentation
fermentation
Glucose
Saccharomyces cerevisiae
D-Xylulose Reductase
Gravitation
glucose
History
gravity
Xylitol
engineering
substrate
Aldehyde Reductase
Substrates
history
Glycerol

ASJC Scopus subject areas

  • Biotechnology
  • !!Applied Microbiology and Biotechnology
  • !!Renewable Energy, Sustainability and the Environment
  • !!Energy(all)
  • !!Management, Monitoring, Policy and Law

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Saccharomyces cerevisiae strain comparison in glucose-xylose fermentations on defined substrates and in high-gravity SSCF : Convergence in strain performance despite differences in genetic and evolutionary engineering history. / Novy, Vera; Wang, Ruifei; Westman, Johan O.; Franzén, Carl Johan; Nidetzky, Bernd.

in: Biotechnology for Biofuels, Jahrgang 10, Nr. 1, 205, 04.09.2017.

Publikation: Beitrag in einer FachzeitschriftReview eines Fachbereichs (Review article)ForschungBegutachtung

@article{af9f1e30839548f5a8567fc518bd10c4,
title = "Saccharomyces cerevisiae strain comparison in glucose-xylose fermentations on defined substrates and in high-gravity SSCF: Convergence in strain performance despite differences in genetic and evolutionary engineering history",
abstract = "Background: The most advanced strains of xylose-fermenting Saccharomyces cerevisiae still utilize xylose far less efficiently than glucose, despite the extensive metabolic and evolutionary engineering applied in their development. Systematic comparison of strains across literature is difficult due to widely varying conditions used for determining key physiological parameters. Here, we evaluate an industrial and a laboratory S. cerevisiae strain, which has the assimilation of xylose via xylitol in common, but differ fundamentally in the history of their adaptive laboratory evolution development, and in the cofactor specificity of the xylose reductase (XR) and xylitol dehydrogenase (XDH). Results: In xylose and mixed glucose-xylose shaken bottle fermentations, with and without addition of inhibitor-rich wheat straw hydrolyzate, the specific xylose uptake rate of KE6-12.A (0.27-1.08 g g CDW -1 h-1) was 1.1 to twofold higher than that of IBB10B05 (0.10-0.82 g g CDW -1 h-1). KE6-12.A further showed a 1.1 to ninefold higher glycerol yield (0.08-0.15 g g-1) than IBB10B05 (0.01-0.09 g g-1). However, the ethanol yield (0.30-0.40 g g-1), xylitol yield (0.08-0.26 g g-1), and maximum specific growth rate (0.04-0.27 h-1) were in close range for both strains. The robustness of flocculating variants of KE6-12.A (KE-Flow) and IBB10B05 (B-Flow) was analyzed in high-gravity simultaneous saccharification and co-fermentation. As in shaken bottles, KE-Flow showed faster xylose conversion and higher glycerol formation than B-Flow, but final ethanol titres (61 g L-1) and cell viability were again comparable for both strains. Conclusions: Individual specific traits, elicited by the engineering strategy, can affect global physiological parameters of S. cerevisiae in different and, sometimes, unpredictable ways. The industrial strain background and prolonged evolution history in KE6-12.A improved the specific xylose uptake rate more substantially than the superior XR, XDH, and xylulokinase activities were able to elicit in IBB10B05. Use of an engineered XR/XDH pathway in IBB10B05 resulted in a lower glycerol rather than a lower xylitol yield. However, the strain development programs were remarkably convergent in terms of the achieved overall strain performance. This highlights the importance of comparative strain evaluation to advance the engineering strategies for next-generation S. cerevisiae strain development.",
author = "Vera Novy and Ruifei Wang and Westman, {Johan O.} and Franz{\'e}n, {Carl Johan} and Bernd Nidetzky",
year = "2017",
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doi = "10.1186/s13068-017-0887-9",
language = "English",
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journal = "Biotechnology for Biofuels",
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TY - JOUR

T1 - Saccharomyces cerevisiae strain comparison in glucose-xylose fermentations on defined substrates and in high-gravity SSCF

T2 - Convergence in strain performance despite differences in genetic and evolutionary engineering history

AU - Novy, Vera

AU - Wang, Ruifei

AU - Westman, Johan O.

AU - Franzén, Carl Johan

AU - Nidetzky, Bernd

PY - 2017/9/4

Y1 - 2017/9/4

N2 - Background: The most advanced strains of xylose-fermenting Saccharomyces cerevisiae still utilize xylose far less efficiently than glucose, despite the extensive metabolic and evolutionary engineering applied in their development. Systematic comparison of strains across literature is difficult due to widely varying conditions used for determining key physiological parameters. Here, we evaluate an industrial and a laboratory S. cerevisiae strain, which has the assimilation of xylose via xylitol in common, but differ fundamentally in the history of their adaptive laboratory evolution development, and in the cofactor specificity of the xylose reductase (XR) and xylitol dehydrogenase (XDH). Results: In xylose and mixed glucose-xylose shaken bottle fermentations, with and without addition of inhibitor-rich wheat straw hydrolyzate, the specific xylose uptake rate of KE6-12.A (0.27-1.08 g g CDW -1 h-1) was 1.1 to twofold higher than that of IBB10B05 (0.10-0.82 g g CDW -1 h-1). KE6-12.A further showed a 1.1 to ninefold higher glycerol yield (0.08-0.15 g g-1) than IBB10B05 (0.01-0.09 g g-1). However, the ethanol yield (0.30-0.40 g g-1), xylitol yield (0.08-0.26 g g-1), and maximum specific growth rate (0.04-0.27 h-1) were in close range for both strains. The robustness of flocculating variants of KE6-12.A (KE-Flow) and IBB10B05 (B-Flow) was analyzed in high-gravity simultaneous saccharification and co-fermentation. As in shaken bottles, KE-Flow showed faster xylose conversion and higher glycerol formation than B-Flow, but final ethanol titres (61 g L-1) and cell viability were again comparable for both strains. Conclusions: Individual specific traits, elicited by the engineering strategy, can affect global physiological parameters of S. cerevisiae in different and, sometimes, unpredictable ways. The industrial strain background and prolonged evolution history in KE6-12.A improved the specific xylose uptake rate more substantially than the superior XR, XDH, and xylulokinase activities were able to elicit in IBB10B05. Use of an engineered XR/XDH pathway in IBB10B05 resulted in a lower glycerol rather than a lower xylitol yield. However, the strain development programs were remarkably convergent in terms of the achieved overall strain performance. This highlights the importance of comparative strain evaluation to advance the engineering strategies for next-generation S. cerevisiae strain development.

AB - Background: The most advanced strains of xylose-fermenting Saccharomyces cerevisiae still utilize xylose far less efficiently than glucose, despite the extensive metabolic and evolutionary engineering applied in their development. Systematic comparison of strains across literature is difficult due to widely varying conditions used for determining key physiological parameters. Here, we evaluate an industrial and a laboratory S. cerevisiae strain, which has the assimilation of xylose via xylitol in common, but differ fundamentally in the history of their adaptive laboratory evolution development, and in the cofactor specificity of the xylose reductase (XR) and xylitol dehydrogenase (XDH). Results: In xylose and mixed glucose-xylose shaken bottle fermentations, with and without addition of inhibitor-rich wheat straw hydrolyzate, the specific xylose uptake rate of KE6-12.A (0.27-1.08 g g CDW -1 h-1) was 1.1 to twofold higher than that of IBB10B05 (0.10-0.82 g g CDW -1 h-1). KE6-12.A further showed a 1.1 to ninefold higher glycerol yield (0.08-0.15 g g-1) than IBB10B05 (0.01-0.09 g g-1). However, the ethanol yield (0.30-0.40 g g-1), xylitol yield (0.08-0.26 g g-1), and maximum specific growth rate (0.04-0.27 h-1) were in close range for both strains. The robustness of flocculating variants of KE6-12.A (KE-Flow) and IBB10B05 (B-Flow) was analyzed in high-gravity simultaneous saccharification and co-fermentation. As in shaken bottles, KE-Flow showed faster xylose conversion and higher glycerol formation than B-Flow, but final ethanol titres (61 g L-1) and cell viability were again comparable for both strains. Conclusions: Individual specific traits, elicited by the engineering strategy, can affect global physiological parameters of S. cerevisiae in different and, sometimes, unpredictable ways. The industrial strain background and prolonged evolution history in KE6-12.A improved the specific xylose uptake rate more substantially than the superior XR, XDH, and xylulokinase activities were able to elicit in IBB10B05. Use of an engineered XR/XDH pathway in IBB10B05 resulted in a lower glycerol rather than a lower xylitol yield. However, the strain development programs were remarkably convergent in terms of the achieved overall strain performance. This highlights the importance of comparative strain evaluation to advance the engineering strategies for next-generation S. cerevisiae strain development.

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U2 - 10.1186/s13068-017-0887-9

DO - 10.1186/s13068-017-0887-9

M3 - Review article

VL - 10

JO - Biotechnology for Biofuels

JF - Biotechnology for Biofuels

SN - 1754-6834

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