Saccharomyces cerevisiae engineered to produce D-xylonate

Mervi H. Toivari*, Laura Ruohonen, Peter Richard, Merja Penttila, Marilyn G. Wiebe

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Saccharomyces cerevisiae was engineered to produce D-xylonate by introducing the Trichoderma reesei xyd1 gene, encoding a D-xylose dehydrogenase. D-xylonate was not toxic to S. cerevisiae, and the cells were able to export D-xylonate produced in the cytoplasm to the supernatant. Up to 3.8 g of D-xylonate per litre, at rates of 25-36 mg of D-xylonate per litre per hour, was produced. Up to 4.8 g of xylitol per litre was also produced. The yield of D-xylonate from D-xylose was approximately 0.4 g of D-xylonate per gramme of D-xylose consumed. Deletion of the aldose reductase encoding gene GRE3 in S. cerevisiae strains expressing xyd1 reduced xylitol production by 67%, increasing the yield of D-xylonate from D-xylose. However, D-xylose uptake was reduced compared to strains containing GRE3, and the total amount of D-xylonate produced was reduced. To determine whether the co-factor NADP(+) was limiting for D-xylonate production the Escherichia coli transhydrogenase encoded by udhA, the Bacillus subtilis glyceraldehyde 3-phosphate dehydrogenase encoded by gapB or the S. cerevisiae glutamate dehydrogenase encoded by GDH2 was co-expressed with xyd1 in the parent and GRE3 deficient strains. Although each of these enzymes enhanced NADPH consumption on D-glucose, they did not enhance D-xylonate production, suggesting that NADP(+) was not the main limitation in the current D-xylonate producing strains.

Original languageEnglish
Pages (from-to)751-760
Number of pages10
JournalApplied Microbiology and Biotechnology
Volume88
Issue number3
DOIs
Publication statusPublished - Oct 2010
MoE publication typeA1 Journal article-refereed

Keywords

  • D-xylonic acid
  • D-xylose
  • S. cerevisiae
  • Phosphoglucose isomerase
  • Redox balance
  • D-XYLOSE METABOLISM
  • L-LACTIC ACID
  • GLUCONOBACTER-OXYDANS
  • YEAST
  • REDUCTASE
  • GENE
  • DEHYDROGENASE
  • STRAINS
  • ALDOSE
  • IDENTIFICATION

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