title: Saccharomycesand non-SaccharomycesCompetition during Microvinification under Different Sugar and Nitrogen Conditions.
abstract: The inoculation of wines with autochthonous yeast allows obtaining complex wines with a peculiar microbial footprint characteristic from a wine region. Mixed inoculation of non-Saccharomycesyeasts andS. cerevisiaeis of interest for the wine industry for technological and sensory reasons. However, the interactions between these yeasts are not well understood, especially those regarding the availability of nutrients. The aim of the present study was to analyze the effect of nitrogen and sugar concentration on the evolution of mixed yeast populations on controlled laboratory-scale fermentations monitored by density, plate culturing, PCR-DGGE and sugar and nitrogen consumption. Furthermore, the effect of the time of inoculation ofSaccharomyces cerevisiaerespect the initial co-inoculation of three non-Saccharomycesyeasts was evaluated over the evolution of fermentation. Our results have shown thatS. cerevisiaeinoculation during the first 48 h conferred a stabilizing effect over the fermentations with non-Saccharomycesstrains tested and, generally, reduced yeast diversity at the end of the fermentation. On the other hand, nitrogen limitation increased the time of fermentation and also the proportion of non-Saccharomycesyeasts at mid and final fermentation. High sugar concentration resulted in different proportions of the inoculated yeast depending on the time ofS. cerevisiaeinoculation. This work emphasizes the importance of the concentration of nutrients on the evolution of mixed fermentations and points to the optimal conditions for a stable fermentation in which the inoculated yeasts survived until the end.
authors.affiliation: Biotecnología Enológica, Department Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Jessica
authors.initials: J
authors.lastname: Lleixà
authors.affiliation: Biotecnología Enológica, Department Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Manzano
authors.affiliation: Biotecnología Enológica, Department Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Mas
authors.affiliation: Biotecnología Enológica, Department Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: María Del C
authors.initials: MD
authors.lastname: Portillo
keywords: Hanseniaspora; Starmarella; Torulaspora; fermentation; wine