title: Metabolic engineering of Saccharomyces cerevisiae for conversion of D-glucose to xylitol and other five-carbon sugars and sugar alcohols.
abstract: Recombinant Saccharomyces cerevisiae strains that produce the sugar alcohols xylitol and ribitol and the pentose sugar D-ribose from D-glucose in a single fermentation step are described. A transketolase-deficient S. cerevisiae strain accumulated D-xylulose 5-phosphate intracellularly and released ribitol and pentose sugars (D-ribose, D-ribulose, and D-xylulose) into the growth medium. Expression of the xylitol dehydrogenase-encoding gene XYL2 of Pichia stipitis in the transketolase-deficient strain resulted in an 8.5-fold enhancement of the total amount of the excreted sugar alcohols ribitol and xylitol. The additional introduction of the 2-deoxy-glucose 6-phosphate phosphatase-encoding gene DOG1 into the transketolase-deficient strain expressing the XYL2 gene resulted in a further 1.6-fold increase in ribitol production. Finally, deletion of the endogenous xylulokinase-encoding gene XKS1 was necessary to increase the amount of xylitol to 50% of the 5-carbon sugar alcohols excreted.
authors.affiliation: VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo, Finland. Mervi.Toivari@vtt.fi
authors.forename: Mervi H
authors.initials: MH
authors.lastname: Toivari
authors.forename: Laura
authors.initials: L
authors.lastname: Ruohonen
authors.forename: Andrei N
authors.initials: AN
authors.lastname: Miasnikov
authors.forename: Peter
authors.initials: P
authors.lastname: Richard
authors.forename: Merja
authors.initials: M
authors.lastname: Penttilä
mesh_terms: D001709:Biotechnology / Q000379:methods; D003470:Culture Media; D050542:D-Xylulose Reductase / Q000235:genetics; D005818:Genetic Engineering / Q000379:methods*; D005947:Glucose / Q000378:metabolism*; D010429:Pentoses / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic; D012255:Ribitol / Q000378:metabolism*; D012266:Ribose / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D014174:Transketolase / Q000172:deficiency / Q000235:genetics; D014993:Xylitol / Q000378:metabolism*
chemical_list: D003470:Culture Media; D010429:Pentoses; D029701:Saccharomyces cerevisiae Proteins; D012255:Ribitol; D012266:Ribose; D050542:D-Xylulose Reductase; D014174:Transketolase; C093600:DOG2 protein, S cerevisiae; D010744:Phosphoric Monoester Hydrolases; D005947:Glucose; D014993:Xylitol