Metabolic flux analysis of xylose metabolism in recombinant Saccharomyces cerevisiae using continuous culture

Juha Pekka Pitkänen, Aristos Aristidou, Laura Salusjärvi, Laura Ruohonen, Merja Penttilä

    Research output: Contribution to journalArticleScientificpeer-review

    83 Citations (Scopus)


    This study focused on elucidating metabolism of xylose in a Saccharomyces cerevisiae strain that overexpresses xylose reductase and xylitol dehydrogenase from Pichia stipitis, as well as the endogenous xylulokinase. The influence of xylose on overall metabolism was examined supplemented with low glucose levels with emphasis on two potential bottlenecks; cofactor requirements and xylose uptake. Results of metabolic flux analysis in continuous cultivations show changes in central metabolism due to the cofactor imbalance imposed by the two-step oxidoreductase reaction of xylose to xylulose. A comparison between cultivations on 27:3 g/L xylose-glucose mixture and 10 g/L glucose revealed that the NADPH-generating flux from glucose-6-phosphate to ribulose-5-phosphate was almost tenfold higher on xylose-glucose mixture and due to the loss of carbon in that pathway the total flux to pyruvate was only around 60% of that on glucose. As a consequence also the fluxes in the citric acid cycle were reduced to around 60%. As the glucose level was decreased to 0.1 g/L the fluxes to pyruvate and in the citric acid cycle were further reduced to 30% and 20%, respectively. The results from in vitro and in vivo xylose uptake measurements showed that the specific xylose uptake rate was highest at the lowest glucose level, 0.1 g/L.

    Original languageEnglish
    Pages (from-to)16-31
    JournalMetabolic Engineering
    Issue number1
    Publication statusPublished - 1 Jan 2003
    MoE publication typeA1 Journal article-refereed


    • Ethanol
    • Metabolic flux analysis
    • Saccharomyces cerevisiae
    • Xylitol
    • Xylose
    • Yeast


    Dive into the research topics of 'Metabolic flux analysis of xylose metabolism in recombinant Saccharomyces cerevisiae using continuous culture'. Together they form a unique fingerprint.

    Cite this