Lactic acid production by Candida sonorensis

Kari Koivuranta, Marja Ilmen, P. Suominen, Aristos Aristidou, V. Rajgarhia, Laura Ruohonen, Merja Penttilä

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


C. sonorensis readily ferments glucose to ethanol, utilizes several carbon sources other than glucose, and is tolerant to acidic conditions. C. sonorensis was engineered for lactate production by individually expressing different lactate dehydrogenase genes in pyruvate decarboxylase positive and negative strain backgrounds to generate strains with distinctive characteristics. Production of lactate and ethanol from glucose was strongly affected by the deletions of the two pyruvate decarboxylase genes PDC1 and PDC2, the properties of the LDH enzymes, and by LDH enzyme activity which varied with LDH gene copy number. C. sonorensis LDH strains were also shown to ferment xylose to lactic acid efficiently via the endogenous xylose pathway enzymes, e.g. via xylose reductase and xylitol dehydrogenase. An alternative xylose fermentation pathway was introduced into C. sonorensis by expressing the XYLA gene from Piromyces sp. encoding xylose isomerase, and xylose was also shown to be metabolized via this pathway. Co-expression of the XKS1 gene from Saccharomyces cerevisiae encoding xylulokinase with the XYLA gene enhanced fermentation relative to expression of XYLA alone. Deletion of the endogenous reductase and xylitol dehydrogenase genes from a strain expressing xylose isomerase had a positive effect on lactate production from xylose.
Original languageEnglish
Title of host publication3rd European Federation of Biotechnology Conference
Subtitle of host publicationPhysiology of Yeasts and Filamentous Fungi PYFF3
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
ISBN (Electronic)978-951-38-6314-2
ISBN (Print)978-951-38-6313-5
Publication statusPublished - 2007
Event3rd European Federation of Biotechnology Conference : Physiology of Yeasts and Filamentous Fungi - Helsinki, Finland
Duration: 13 Jun 200716 Jun 2007

Publication series

SeriesVTT Symposium


Conference3rd European Federation of Biotechnology Conference
Abbreviated titlePYFF3

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    Koivuranta, K., Ilmen, M., Suominen, P., Aristidou, A., Rajgarhia, V., Ruohonen, L., & Penttilä, M. (2007). Lactic acid production by Candida sonorensis. In 3rd European Federation of Biotechnology Conference: Physiology of Yeasts and Filamentous Fungi PYFF3 (pp. 48). [T37] VTT Technical Research Centre of Finland. VTT Symposium, No. 245