title: Saccharomyces cerevisiae and metabolic activators: HXT3 gene expression and fructose/glucose discrepancy in sluggish fermentation conditions.
abstract: When exposed to mixtures of glucose and fructose, as occurs during the fermentation of grape juice into wine, Saccharomyces cerevisiae uses these sugars at different rates. Moreover, glucose and fructose are transported by the same hexose transporters (HXT), which present a greater affinity for glucose, so that late in fermentation, fructose becomes the predominant sugar. Only a few commercial fermentation activators are available to optimally solve the problems this entails. The aim of this study was to investigate the relation between HXT3 gene expression and fructose/glucose discrepancy in two different media inoculated with a commercial wine strain of S. cerevisiae in the presence of three metabolic activators. Fermentation kinetics, vitality and major metabolites were also measured. Rehydration with ergosterol improved the area under the curve and the growth rate (µmax) in both studied media. Also, the fructose/glucose discrepancy values were improved with all activator treatments, highlighting rehydration in the presence of ascorbic acid. The yeast rehydration process was demonstrated to influence HXT3 expression under the studied conditions. Tetrahydrofolic acid treatment greatly influenced HXT3 gene expression, especially on the 12th day of the fermentation process. To a lesser extent, ergosterol and ascorbic acid also improved this parameter.
authors.affiliation: Tecnología de Alimentos, IRICA, Universidad de Castilla La Mancha, Avda. Camilo José Cela, 10, Edifico Marie Curie, 13071, Ciudad Real, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Díaz-Hellín
authors.affiliation: ProBioVet S.L., IRICA (3rd Floor, Lab. 6), Universidad de Castilla La Mancha, Avda. Camilo José Cela 10, Edifico Marie Curie, 13071, Ciudad Real, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Naranjo
authors.affiliation: Tecnología de Alimentos, IRICA, Universidad de Castilla La Mancha, Avda. Camilo José Cela, 10, Edifico Marie Curie, 13071, Ciudad Real, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Úbeda
authors.affiliation: Tecnología de Alimentos, IRICA, Universidad de Castilla La Mancha, Avda. Camilo José Cela, 10, Edifico Marie Curie, 13071, Ciudad Real, Spain. ana.briones@uclm.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Briones
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D004875:Ergosterol / Q000494:pharmacology; D005285:Fermentation; D005632:Fructose / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D013763:Tetrahydrofolates / Q000494:pharmacology; D014920:Wine / Q000032:analysis / Q000382:microbiology*
chemical_list: D051246:Glucose Transport Proteins, Facilitative; C090595:HXT3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013763:Tetrahydrofolates; D005632:Fructose; C030371:5,6,7,8-tetrahydrofolic acid; D005947:Glucose; D001205:Ascorbic Acid; D004875:Ergosterol
keywords: Fructose/glucose discrepancy; HXT3; S. cerevisiae; Wine yeast; Yeast vitality; qRT-PCR