Efficient production of L-lactic acid from xylose by metabolically engineered yeast Pichia stipitis

Marja Ilmén, Kari Koivuranta, Laura Ruohonen, Pirkko Suominen, Merja Penttilä

    Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsScientific

    Abstract

    Pichia stipitis, a yeast which ferments naturally xylose, was genetically engineered for L-(+)-lactate production. A P. stipitis strain expressing the L-lactate dehydrogenase (LDH) from Lactobacillus helveticus under the control of the P. stipitis fermentative ADH1 promoter was constructed. Either xylose or glucose was used as the carbon source for lactate production under oxygen restricted conditions. Remarkably, the constructed P. stipitis strain produced a higher lactate concentration and yield on xylose than on glucose. Lactate accumulated as the main product on xylose-containing medium: 58 g/l lactate was produced from 100 g/l xylose. Relatively efficient lactate production was also observed on glucose medium, 41 g/l lactate was produced at a yield of 0.44 g/g glucose. Lactate was produced at the expense of ethanol production which was decreased to approximately 20% of the wild type levels on xylose-containing medium and to 75% on glucose-containing medium. Thus, LDH competed efficiently with the ethanol pathway for pyruvate, even though the pathway from pyruvate to ethanol was intact.
    Original languageEnglish
    Title of host publicationInternational Specialised Symposium on Yeasts ISSY25
    Subtitle of host publicationSystems Biology of Yeasts - from Models to Applications
    EditorsAnnemari Kuokka, Merja Penttilä
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Pages150
    ISBN (Electronic)951-38-6308-5
    ISBN (Print)951-38-6307-7
    Publication statusPublished - 2006
    EventInternational Specialised Symposium on Yeasts, ISSY 25 - Espoo, Finland
    Duration: 18 Jun 200621 Jun 2006

    Publication series

    SeriesVTT Symposium
    Number242
    ISSN0357-9387

    Conference

    ConferenceInternational Specialised Symposium on Yeasts, ISSY 25
    Abbreviated titleISSY 25
    CountryFinland
    CityEspoo
    Period18/06/0621/06/06

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