title: Cloning novel sugar transporters from Scheffersomyces (Pichia) stipitis allowing D-xylose fermentation by recombinant Saccharomyces cerevisiae.
abstract: OBJECTIVE
  Since uptake of xylose limits its fermentation, we aimed to identify novel sugar transporters from Scheffersomyces stipitis that allow xylose uptake and fermentation by engineered Saccharomyces cerevisiae.
  
  
  RESULTS
  An hxt-null S. cerevisiae strain, lacking the major hexose transporters (hxt1Δ-hxt7Δ and gal2Δ) but having high xylose reductase, xylitol dehydrogenase and xylulokinase activities, was transformed with a genomic DNA library from S. stipitis. Four plasmids allowing growth on xylose contained three genes encoding sugar transporters: the previously characterized XUT1 permease, and two new genes (HXT2.6 and QUP2) not previously identified as xylose transporters. High cell density fermentations with the recombinant strains showed that the XUT1 gene allowed ethanol production from xylose or xylose plus glucose as carbon sources, while the HXT2.6 permease produced both ethanol and xylitol, and the strain expressing the QUP2 gene produced mainly xylitol during xylose consumption.
  
  
  CONCLUSIONS
  Cloning novel sugar transporters not previously identified in the S. stipitis genome using an hxt-null S. cerevisiae strain with a high xylose-utilizing pathway provides novel promising target genes for improved lignocellulosic ethanol production by yeasts.
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
authors.forename: Belisa B
authors.initials: BB
authors.lastname: de Sales
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
authors.forename: Bruna
authors.initials: B
authors.lastname: Scheid
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
authors.forename: Davi L
authors.initials: DL
authors.lastname: Gonçalves
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
authors.forename: Marilia M
authors.initials: MM
authors.lastname: Knychala
authors.affiliation: Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-0046, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Matsushika
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio De Janeiro, RJ, 21941-909, Brazil.
authors.forename: Elba P S
authors.initials: EP
authors.lastname: Bon
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil. boris.stambuk@ufsc.br.
authors.forename: Boris U
authors.initials: BU
authors.lastname: Stambuk
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D003001:Cloning, Molecular; D003470:Culture Media / Q000737:chemistry; D003600:Cytosol / Q000737:chemistry; D005285:Fermentation; D015870:Gene Expression; D005820:Genetic Testing; D015698:Genomic Library; D051246:Glucose Transport Proteins, Facilitative / Q000235:genetics / Q000378:metabolism*; D060847:Metabolic Engineering; D010843:Pichia / Q000201:enzymology* / Q000235:genetics; D010957:Plasmids; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D003470:Culture Media; D051246:Glucose Transport Proteins, Facilitative; D011994:Recombinant Proteins; D014994:Xylose
keywords: Bioethanol; Fermentation; Saccharomyces cerevisiae; Scheffersomyces stipitis; Sugar transporter; Xylose