Non-canonical regulation of glutathione and trehalose biosynthesis characterizes non-Saccharomyces wine yeasts with poor performance in active dry yeast production

Abstract

Several yeast species, belonging to Saccharomyces and non-Saccharomyces genera, play fundamental roles during spontaneous must grape fermentation, and recent studies have shown that mixed fermentations, co-inoculated with S. cerevisiae and non-Saccharomyces strains, can improve wine organoleptic properties. During active dry yeast (ADY) production, antioxidant systems play an essential role in yeast survival and vitality as both biomass propagation and dehydration cause cellular oxidative stress and negatively affect technological performance. Mechanisms for adaptation and resistance to desiccation have been described for S. cerevisiae, but no data are available on the physiology and oxidative stress response of non-Saccharomyces wine yeasts and their potential impact on ADY production. In this study we analyzed the oxidative stress response in several non-Saccharomyces yeast species by measuring the activity of reactive oxygen species (ROS) scavenging enzymes, e.g., catalase and glutathione reductase, accumulation of protective metabolites, e.g., trehalose and reduced glutathione (GSH), and lipid and protein oxidation levels. Our data suggest that non-canonical regulation of glutathione and trehalose biosynthesis could cause poor fermentative performance after ADY production, as it corroborates the corrective effect of antioxidant treatments, during biomass propagation, with both pure chemicals and food-grade argan oil.

Genomic insights into the glutathione metabolism of the non-conventional wine yeast <i>Starmerella bacillaris</i>

“…Interestingly, in the tested conditions, S. bacillaris PAS13 produces higher GSH concentrations than S. cerevisiae EC1118. These results are consistent with those of Gamero-Sandemetrio et al (2018), who tested the GSH production of different non-Saccharomyces strains during the active dry yeast manufacturing process; among them, C. stellata (the previous taxonomic classification of S. bacillaris) was the only non-Saccharomyces species that produced higher GSH levels than S. cerevisiae. S. cerevisiae GSH precursor and catabolite contents were significantly higher than for S. bacillaris strains, suggesting a different GSH turnover.…”

Torulaspora delbrueckii: Towards Innovating in the Legendary Baking and Brewing Industries

“…Oppositely, Torulaspora delbrueckii strains under hyperosmotic/frozen stresses into sweet dough have shown the ability to adapt promptly to high-osmotic-pressure environments which correlates in part with a low-invertase activity, as well as a slow rate of trehalose mobilisation, displaying a higher accumulation of trehalose than S. cerevisiae [8,27]. Moreover, the intracellular trehalose accumulation, induced by desiccation of T. delbrueckii, protects the yeast cell and presents a lower oxidative stress, which correlates with a higher fermentative capacity, when compared to other nonconventional yeasts [40]. The trehalose content may possibly be correlated to their types of trehalase.…”

Contribution of non‐ Saccharomyces yeasts to increase glutathione concentration in wine

“…The yeast S. cerevisiae has been the benchmark starter culture for many decades, inoculated into grape musts to overpower the native microbiota and provide a more controlled and predictable fermentation. A growing trend in oenology is, however, the use of multi‐starters containing representatives of non‐conventional yeasts (Gamero‐Sandemetrio et al 2018). The so‐called group of non‐ Saccharomyces yeasts is becoming popular for a myriad of reasons, but the ultimate goal is to improve fermentation and obtain wines with greater complexity, distinctiveness and quality (Roudil et al 2020).…”