Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Metabolic engineering strategies for optimizing acetate reduction, ethanol yield and osmotolerance in Saccharomyces cerevisiae
KTH, School of Biotechnology (BIO), Industrial Biotechnology. Delft University Technology Netherlands.
2017 (English)In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 10, 107Article in journal (Refereed) Published
Abstract [en]

Background: Glycerol, whose formation contributes to cellular redox balancing and osmoregulation in Saccharomyces cerevisiae, is an important by-product of yeast-based bioethanol production. Replacing the glycerol pathway by an engineered pathway for NAD(+)-dependent acetate reduction has been shown to improve ethanol yields and contribute to detoxification of acetate-containing media. However, the osmosensitivity of glycerol non-producing strains limits their applicability in high-osmolarity industrial processes. This study explores engineering strategies for minimizing glycerol production by acetate-reducing strains, while retaining osmotolerance. Results: GPD2 encodes one of two S. cerevisiae isoenzymes of NAD(+)-dependent glycerol-3-phosphate dehydrogenase (G3PDH). Its deletion in an acetate-reducing strain yielded a fourfold lower glycerol production in anaerobic, low-osmolarity cultures but hardly affected glycerol production at high osmolarity. Replacement of both native G3PDHs by an archaeal NADP(+)-preferring enzyme, combined with deletion of ALD6, yielded an acetate-reducing strain the phenotype of which resembled that of a glycerol-negative gpd1 Delta gpd2 Delta strain in low-osmolarity cultures. This strain grew anaerobically at high osmolarity (1 mol L-1 glucose), while consuming acetate and producing virtually no extracellular glycerol. Its ethanol yield in high-osmolarity cultures was 13% higher than that of an acetate-reducing strain expressing the native glycerol pathway. Conclusions: Deletion of GPD2 provides an attractive strategy for improving product yields of acetate-reducing S. cerevisiae strains in low, but not in high-osmolarity media. Replacement of the native yeast G3PDHs by a heterologous NADP(+)-preferring enzyme, combined with deletion of ALD6, virtually eliminated glycerol production in high-osmolarity cultures while enabling efficient reduction of acetate to ethanol. After further optimization of growth kinetics, this strategy for uncoupling the roles of glycerol formation in redox homeostasis and osmotolerance can be applicable for improving performance of industrial strains in high-gravity acetate-containing processes.

Place, publisher, year, edition, pages
BioMed Central, 2017. Vol. 10, 107
Keyword [en]
Yeast, NADH, NADPH, Redox engineering, Acetic acid, Osmotic stress, Bioethanol
National Category
Bioprocess Technology
Identifiers
URN: urn:nbn:se:kth:diva-208845DOI: 10.1186/s13068-017-0791-3ISI: 000401619500001PubMedID: 28450888OAI: oai:DiVA.org:kth-208845DiVA: diva2:1108752
Note

QC 20170613

Available from: 2017-06-13 Created: 2017-06-13 Last updated: 2017-06-13Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
van Maris, Antonius J. A.
By organisation
Industrial Biotechnology
In the same journal
Biotechnology for Biofuels
Bioprocess Technology

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf