Suchergebnisse

In winemaking, the use of alternative yeast starters is becoming increasingly popular. They contribute to the diversity and complexity of wine sensory features and are typically used in combination with Saccharomyces cerevisiae , to ensure complete fermentation. This practice has drawn the interest on interactions between different oenological yeasts, which are also relevant in spontaneous and conventional fermentations, or in the vineyard. Although several interactions have been described and some mechanisms have been suggested, the possible involvement of extracellular vesicles (EVs) has not yet been considered. This work describes the production of EVs by six wine yeast species (S. cerevisiae , Torulaspora delbrueckii , Lachancea thermotolerans , Hanseniaspora uvarum , Candida sake and Metschnikowia pulcherrima ) in synthetic grape must. Proteomic analysis of EV‐enriched fractions from S. cerevisiae and T. delbrueckii showed enrichment in glycolytic enzymes and cell‐wall‐related proteins. The most abundant protein found in S. cerevisiae , T. delbrueckii and L. thermotolerans EV‐enriched fractions was the enzyme exo‐1,3‐β‐glucanase. However, this protein was not involved in the here‐observed negative impact of T. delbrueckii extracellular fractions on the growth of other yeast species. These findings suggest that EVs may play a role in fungal interactions during wine fermentation and other aspects of wine yeast biology. ; This work was funded by the Spanish Government through grants AGL2015-63629-R (co-financed by FEDER funds), PCI2018-092949 (co-funded by ERA-CoBioTech) and BES-2016-077557 (training contract for AM). JT is funded by FGCSIC by the COMFUTURO program. ; Peer reviewed

[GAR+] prion-like elements partially relieve carbon catabolite repression in Saccharomyces cerevisiae. They have been hypothesized to contribute to wine yeast survival and alcohol level reduction, as well as communication with bacteria and stuck fermentation. In this work, we selected [GAR+] derivatives from several genetic backgrounds. They were characterized for phenotypic penetrance, heritability and confirmed as prion-like through curing by desiccation. In terms of fermentation kinetics, the impact of the prion on anaerobic wine fermentation (natural grape juice) was either neutral or negative, depending on the genetic background. Likewise, residual sugars were higher or similar for [GAR+] as compared to the cognate [gar-] strains. The prions had little or no impact on glycerol and ethanol yields; while acetic acid yields experienced the highest variations between [GAR+] and [gar-] strains. Strains analyzed under aerobic conditions followed the same pattern, with either little or no impact on fermentation kinetics, ethanol or glycerol yield; and a clearer influence on volatile acidity. Although no clear winemaking advantages were found for [GAR+] strains in this work, they might eventually show interest for some combinations of genetic background or winemaking conditions, e.g., for reducing acetic acid yield under aerated fermentation. ; This work was funded by the Spanish Ministry of Science, Innovation and Universities by grant AGL2015-63629-R (co-financed by FEDER funds). AM and AR were recipients to FPI contract, and JC of Formación Postdoctoral contract, all from the Spanish Government. JT was funded by FGCSIC by the COMFUTURO program. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). ; Peer reviewed