title: Expression and functional studies of genes involved in transport and metabolism of glycerol in Pachysolen tannophilus.
abstract: BACKGROUND
  Pachysolen tannophilus is a non-conventional yeast, which can metabolize many of the carbon sources found in low cost feedstocks including glycerol and xylose. The xylose utilisation pathways have been extensively studied in this organism. However, the mechanism behind glycerol metabolism is poorly understood. Using the recently published genome sequence of P. tannophilus CBS4044, we searched for genes with functions in glycerol transport and metabolism by performing a BLAST search using the sequences of the relevant genes from Saccharomyces cerevisiae as queries.
  
  
  RESULTS
  Quantitative real-time PCR was performed to unveil the expression patterns of these genes during growth of P. tannophilus on glycerol and glucose as sole carbon sources. The genes predicted to be involved in glycerol transport in P. tannophilus were expressed in S. cerevisiae to validate their function. The S. cerevisiae strains transformed with heterologous genes showed improved growth and glycerol consumption rates with glycerol as the sole carbon source.
  
  
  CONCLUSIONS
  P. tannophilus has characteristics relevant for a microbial cell factory to be applied in a biorefinery setting, i.e. its ability to utilise the carbon sources such as xylose and glycerol. However, the strain is not currently amenable to genetic modification and transformation. Heterologous expression of the glycerol transporters from P. tannophilus, which has a relatively high growth rate on glycerol, could be used as an approach for improving the efficiency of glycerol assimilation in other well characterized and applied cell factories such as S. cerevisiae.
authors.affiliation: Department of Systems Biology, Building 223, Søltofts Plads, Technical University of Denmark, Lyngby 2800 Kgs, Denmark.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Liu
authors.forename: Uffe Hasbro
authors.initials: UH
authors.lastname: Mortensen
authors.forename: Mhairi
authors.initials: M
authors.lastname: Workman
mesh_terms: D000595:Amino Acid Sequence; D030541:Databases, Genetic; D005656:Fungal Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D008565:Membrane Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D004718:Saccharomycetales / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014994:Xylose / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D014994:Xylose; D005990:Glycerol