Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub

    Description

    Native strains of Saccharomyces cerevisiae do not assimilate xylose. S. cerevisiae engineered for D-xylose utilization through the heterologous expression of genes for aldose reductase ( XYL1), xylitol dehydrogenase (XYL2), and D-xylulokinase ( XYL3 or XKS1) produce only limited amounts of ethanol in xylose medium. In recombinant S. cerevisiae expressing XYL1, XYL2, and XYL3, mRNA transcript levels for glycolytic, fermentative, and pentose phosphate enzymes did not change significantly on glucose or xylose under aeration or oxygen limitation. However, expression of genes encoding the tricarboxylic acid cycle, respiration enzymes (HXK1, ADH2, COX13, NDI1, and NDE1), and regulatory proteins (HAP4 and MTH1) increased significantly when cells were cultivated on xylose, and the genes for respiration were even more elevated under oxygen limitation. These results suggest that recombinant S. cerevisiae dues not recognize xylose as a fermentable carbon source and that respiratory proteins are induced in response tu cytosolic redox imbalance; however, lower sugar uptake and growth rates on xylose might also induce transcripts for respiration. A petite respiration-deficient mutant (r°) of the engineered strain produced more ethanol and accumulated less xylitol from xylose. It formed characteristic colonies on glucose, but it did not grow on xylose. These results are consistent with the higher respiratory activity of recombinant S. cerevisiae when growing on xylose and with its inability to grow on xylose under anaerobic conditions.

    Publication Notes

    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Jin, Yong-Su; Laplaza, Jose M.; Jeffries, Thomas W. 2004. Saccharomyces cerevisiae engineered for xylose metabolism exhibits a respiratory response. Applied and environmental microbiology. Vol. 70, no. 11 (Nov. 2004): Pages 6816-6825

    Keywords

    Saccharomyces cerevisiae, xylose metabolism, fungi, yeast, ethanol, fermentation

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/9130