Characterization of Indigenous Non-Saccharomyces Yeast Strains with Potential Use in Winemaking

Abstract

Background:The vineyard is a great reservoir of autochthonous yeast strains whose composition is defined by different regional (edaphology, orography or climatology) and anthropological factors (cultivation systems or cultural practices). Most of this yeast diversity corresponds to non-Saccharomyces strains, some of which have potential use in winemaking. Methods: The oenological potential of 29 different native non-Saccharomyces strains belonging to 4 species (Lachancea thermotolerans, Torulaspora delbrueckii, Starmerella bacillaris and Metschnikowia spp.) was evaluated, using the autochthonous Saccharomyces cerevisiae XG3 strain as a control. Microfermentations with pure culture of each strain were performed in duplicate and the basic parameters and major volatiles of wines were analysed following official methodology. The best strain within each species was selected using a quantification matrix including the relevant oenological characteristics. Results: The fermentative ability of non-Saccharomyces was lower than S. cerevisiae in all cases, but with differences among species. L. thermotolerans and T. delbrueckii showed higher fermentation rates than Starm. bacillaris, whereas Metschnikowia spp. presented a low fermentative power. At chemical level all non-Saccharomyces strains reduced the alcoholic content, the higher alcohols and the volatile acidity of wines and increased the content of glycerol, with differences among strains within a given species. T. delbrueckii and L. thermotolerans increased the total acidity of wines. The latter and Metschnikowia spp. strains produced lactic acid, which decreased the wine pH in the case of L. thermotolerans. According to their oenological traits the best rated strains of each species were Lt93, Td315, Mf278 and Sb474. In addition, the data obtained in pure fermentations were correlated to those chemical and aromatic compounds obtained with these non-Saccharomyces strains in sequential fermentations. Conclusions: Autochthonous strains of non-Saccharomyces yeast species contribute distinctive chemical characteristics to the wines. The correlations observed between wines fermented with the different non-Saccharomyces indigenous strains in pure and sequential fermentations suggest that their contribution to wine properties remains stable regardless of must composition or winemaking techniques. Keywords: non-Saccharomyces; autochthonous yeasts; chemical composition; Pearson correlation;Lachancea thermotolerans; Torulaspora delbrueckii; Starmerella bacillaris; Metschnikowia ScXG3 6.8 ± 0.0 a 0.60 ± 0.03 a 0.1 ± 0.0 a 3.5 ± 0.1 a 0.2 ± 0.1 a 3.8 ± 0.3 a 10.05 ± 0.07 a 0.42 ± 0.00 a 3.66 ± 0.01 ab Lt3 7.9 ± 0.1 ab 0.39 ± 0.06 1.7 ± 0.6 2.6 ± 0.3 6.1 ± 7.6 5.6 ± 1.0 9.12 ± 0.40 0.39 ± 0.00 3.58 ± 0.09 Lt18 7.4 ± 0.1 ab 0.38 ± 0.01 0.8 ± 0.3 2.85 ± 0.2 20.3 ± 10.7 5.6 ± 0.3 8.08 ± 0.11 0.38 ± 0.02 3.58 ± 0.07 Lt93 8.0 ± 0.0 a 0.43 ± 0.01 2.6 ± 1.0 2.3 ± 0.3 0.8 ± 0.9 6.1 ± 0.2 9.02 ± 0.11 0.38 ± 0.01 3.53 ± 0.08 Lt132 7.6 ± 0.6 ab 0.40 ± 0.04 1.5 ± 1.1 2.5 ± 0.5 9.8 ± 5.3 5.5 ...

A comparative study of Lachancea thermotolerans fermentative performance under standardized wine production conditions

“…This finding should be interpreted carefully, as higher alcohols can contribute both desirable and undesirable aromas to the wine, depending on the specific odor descriptor of each compound and its olfactory threshold. Nevertheless, among several non- Saccharomyces species, L. thermotolerans seems to have the greatest impact on higher alcohols ( Castrillo & Blanco, 2023 ).…”

Genetic diversity of non-Saccharomyces yeasts associated with spontaneous fermentation of Cabernet Sauvignon wines from Ningxia, China

“…Recently, the enological behaviors and potential application of indigenous non- Saccharomyces have drawn widespread attention ( Zhao et al, 2022 ; Castrillo and Blanco, 2023 ). Although H. uvarum , M. pulcherrima and C. zemplinina are the abundant yeast species during wine fermentation in this study.…”

Non-Saccharomyces Yeast Strains, Aromatic Compounds and Sensory Analysis of Italy and Negra Criolla Pisco from the Moquegua Region of Peru

“…Yeasts are physiologically classified with respect to the type of energy-generating process involved in their sugar metabolism, namely non-, facultative-or obligate fermentative yeasts [36]. Regarding this sugar metabolism, M. pulcherrima has been characterized as a strain that follows a respiratory metabolic pathway with slower fermentation yields; therefore, it can be used to reduce the final ethanol concentration in wine [37]. A respiratory metabolic pathway involves tricarboxylic acid (TCA), which can produce different acids that in turn reduce the pH [38], as shown in the present study (Figure 1A,B).…”