Stress Resistance and Adhesive Properties of Commercial Flor and Wine Strains, and Environmental Isolates of Saccharomyces cerevisiae

Michail A Eldarov,Nikolai V Ravin,Maksim Y Shalamitskiy,Daria A Avdanina,Andrey V Mardanov,Tatiana Vybornaya,Tatiana N Tanashchuk,Elena Ivanova,Svetlana A Kishkovskaya

doi:10.3390/fermentation7030188

Michail A Eldarov, Nikolai V Ravin + Show 7 more

Open Access

https://doi.org/10.3390/fermentation7030188

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Abstract

Flor strains of Saccharomyces cerevisiae represent a special group of yeasts used for producing biologically aged wines. We analyzed the collection of commercial wine and flor yeast strains, as well as environmental strains isolated from the surface of grapes growing in vineyards, for resistance to abiotic stresses, adhesive properties, and the ability to form a floating flor. The degree of resistance of commercial strains to ethanol, acetaldehyde, and hydrogen peroxide was generally not higher than that of environmental isolates, some of which had high resistance to the tested stress agents. The relatively low degree of stress resistance of flor strains can be explained both by the peculiarities of their adaptive mechanisms and by differences in the nature of their exposure to various types of stress in the course of biological wine aging and under the experimental conditions we used. The hydrophobicity and adhesive properties of cells were determined by the efficiency of adsorption to polystyrene and the distribution of cells between the aqueous and organic phases. Flor strains were distinguished by a higher degree of hydrophobicity of the cell surface and an increased ability to adhere to polystyrene. A clear correlation between biofilm formation and adhesive properties was also observed for environmental yeast isolates. The overall results of this study indicate that relatively simple tests for cell hydrophobicity can be used for the rapid screening of new candidate flor strains in yeast culture collections and among environmental isolates.

Highlights

Flor strains of Saccharomyces cerevisiae yeasts represent a special group of wine-making microbiota and are used in a number of traditional technologies for producing biologically aged wines [1,2]
We used S. cerevisiae strains from the collection of microorganisms of winemaking of the All-Russian Research Institute of Viticulture and Winemaking “Magarach” of the Russian Academy of Sciences used for making sherry-like (“flor strains”) and ordinary wines (“wine strains”), as well as S. cerevisiae yeast strains isolated in the winemaking seasons of 2016 and 2018 from the surface of grapes growing in vineyards of different climatic zones of Crimea and Rostov area (“environmental strains”)
In our previous studies, detailed biochemical, microbiological, genetic, and oenological characteristics of flor and wine strains from the collection of microorganisms for winemaking “Magarach” as well as yeast strains isolated during the winemaking seasons of 2016 and 2018 from grapes growing in the vineyards of the Crimea and the Rostov region were determined [6,29,34]

Summary

Introduction

Flor strains of Saccharomyces cerevisiae yeasts represent a special group of wine-making microbiota and are used in a number of traditional technologies for producing biologically aged wines [1,2]. Methods of obtaining such wines as Jerez (Spain), Vin Jaune (Jura, France), Vernaccia di Oristano (Sardinia, Italy), and Native dry tokay (Hungary) differ, but they all involve a long biological aging under a yeast biofilm (flor) formed on the surface of fortified fermented wine materials [3,4]. In the process of biological wine ageing, flor yeast encounters high concentrations of ethanol

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