Production of xylitol and other five-carbon sugars and sugar alcohols from D-glucose with Saccharomyces cerevisiae

Merja Toivari, A.N. Miasnikov, Peter Richard, Laura Ruohonen, Merja Penttilä

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


We constructed recombinant Saccharomyces cerevisiae strains deficient in either transketolase or phosphoglucose isomerase activities for production of xylitol, ribitol or ribose from D-glucose via the pentose phosphate pathway (PPP) intermediates D-xylulose 5-phosphate, D-ribulose 5-phosphate or D-ribose 5-phosphate. The transketolase-deficient strains accumulated PPP sugar-phosphates and excreted D-ribulose/D-ribose to the culture medium. Introduction of xylitol dehydrogenase encoding gene XYL2 from Pichia stipitis increased ribitol and xylitol production and concomitantly decreased the amount of D-ribulose/D-ribose. A sugar phosphate phosphatase Dog1p increased ribitol production 1.6-fold, but did not enhance xylitol excretion. Deletion of the xylulokinase encoding gene XKS1 increased the amount of xylitol produced to 50% of the total sugar alcohols (ribitol plus xylitol) produced. The highest yield of xylitol and ribitol obtained with the various transketolase deficient strains studied was 3.6% (w/w) of consumed D-glucose. S. cerevisiae strains deficient in phosphoglucose isomerase activity are unable to grow on D-glucose unless a NADPH-consuming reaction is introduced into the cell (1, 2). We introduced two NADPH-consuming reactions, a NADPH-utilizing glyceraldehyde 3-phosphate dehydrogenase of Bacillus subtilis (GapB) and a NAD-dependent glutamate dehydrogenase (GDH2) of S. cerevisiae into the pgi1-mutant strain in order to produce 5-carbon sugars and sugar alcohols from D-glucose via the PPP. Both of these enzymes enabled growth on D-glucose of the pgi1-mutant strains, as shown for the GDH2 overexpression previously (1). The Dog1p phosphatase was, however, needed for production of 5-carbon sugars and sugar alcohols. On higher D-glucose concentrations the expression of DOG1 together with either GapB or GDH2 reduced growth. The Dog1p may create a futile cycle of phosphorylation and dephosphorylation of glucose 6-phosphate resulting in ATP depletion.
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
MoE publication typeNot Eligible
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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