title: Effects of GPD1 overexpression in Saccharomyces cerevisiae commercial wine yeast strains lacking ALD6 genes.
abstract: The utilization of Saccharomyces cerevisiae strains overproducing glycerol and with a reduced ethanol yield is a potentially valuable strategy for producing wine with decreased ethanol content. However, glycerol overproduction is accompanied by acetate accumulation. In this study, we evaluated the effects of the overexpression of GPD1, coding for glycerol-3-phosphate dehydrogenase, in three commercial wine yeast strains in which the two copies of ALD6 encoding the NADP+-dependent Mg2+-activated cytosolic acetaldehyde dehydrogenase have been deleted. Under wine fermentation conditions, the engineered industrial strains exhibit fermentation performance and growth properties similar to those of the wild type. Acetate was produced at concentrations similar to that of the wild-type strains, whereas sugar was efficiently diverted to glycerol. The ethanol yield of the GPD1 ald6 industrial strains was 15 to 20% lower than that in the controls. However, these strains accumulated acetoin at considerable levels due to inefficient reduction to 2,3-butanediol. Due to the low taste and odor thresholds of acetoin and its negative sensorial impact on wine, novel engineering strategies will be required for a proper adjustment of the metabolites at the acetaldehyde branch point.
authors.affiliation: UMR Sciences pour l'Oenologie, Microbiologie, INRA, 2 Place Viala, F-34060 Montpellier Cedex 1, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Cambon
authors.forename: Virginie
authors.initials: V
authors.lastname: Monteil
authors.forename: Fabienne
authors.initials: F
authors.lastname: Remize
authors.forename: Carole
authors.initials: C
authors.lastname: Camarasa
authors.forename: Sylvie
authors.initials: S
authors.lastname: Dequin
mesh_terms: D000085:Acetates / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000235:genetics*; D003470:Culture Media; D005285:Fermentation; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005818:Genetic Engineering / Q000379:methods; D005990:Glycerol / Q000378:metabolism; D005993:Glycerolphosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D007218:Industrial Microbiology / Q000379:methods; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014920:Wine / Q000382:microbiology*
chemical_list: D000085:Acetates; D003470:Culture Media; D005993:Glycerolphosphate Dehydrogenase; D000445:Aldehyde Oxidoreductases; C018699:aldehyde dehydrogenase (NAD(P)+); D005990:Glycerol