Colonization of Wild Saccharomyces cerevisiae Strains in a New Winery

Hany Abdo,Mario Ventura,Julie Laurent,Claudia R Catacchio,Michèle Guilloux-Bénatier,Hervé Alexandre,Sandrine Rousseaux,Pietro D’Addabbo,Francesco Maria Calabrese,Vanessa David-Vaizant

doi:10.3390/beverages6010009

Abstract

The aim of this work was to study the fungal colonization of a new winery over time, specifically for Saccharomyces cerevisiae. Therefore, we analyzed the flora present before the arrival of the first harvest on the floor, the walls and the equipment of this new winery by Illumina MiSeq. The genus Saccharomyces (≤0.3%) was detected on floor and equipment but the presence of S. cerevisiae species was not reported. Wild S. cerevisiae strains were isolated from a ‘Pied de Cuve’ used during the first vintage to ensure the alcoholic fermentation (AF). Among 25 isolates belonging to this species, 17 different strains were identified highlighting a great intraspecific diversity. S. cerevisiae strains were also isolated from different vats throughout the spontaneous fermentations during the first vintage. The following year, some of these strains were isolated again during AF. Some of them (four) were found in the winery equipment before the arrival of the third harvest suggesting a potential colonization by these strains. To better understand what promotes the yeast colonization of the winery’s environment, the ability to form a biofilm on solid surfaces for eight colonizing or non-colonizing strains was studied. This capacity, different according to the strains, could partly explain the colonization observed for certain strains.

Highlights

In the winemaking process, several practices are used worldwide to ensure the alcoholic fermentation (AF)
The status of the Saccharomyces genus in a new winery was studied in order to provide new knowledge on the presence of this genus on the wine-related environments (WREs) of a new winery, which has never been studied before
Despite the low representation of the genus Saccharomyces, we investigated whether these consisted of the species Saccharomyces cerevisiae by identification of the isolates by PCR-internal transcribed spacer (ITS)

Summary

Introduction

Several practices are used worldwide to ensure the alcoholic fermentation (AF). The use of commercial starters of ADY has become one of the most common practices in winemaking worldwide [1,2] This technique ensures (i) faster AF, (ii) production of desirable metabolites and (iii) reduction of the risk of wine spoilage [3,4,5]. It has been demonstrated that the use of this practice positively impacts the sensory characteristics of wine and enhances its complexity due to the succession of multiple non-Saccharomyces and Saccharomyces species [6,7,8,9,10] This uncontrolled biological process can result in a stuck or sluggish AF and increases the risk of wine spoilage due to the development of undesirable yeasts or bacteria [11,12]. To minimize the risks linked to spontaneous fermentations, winemakers can use a special method called ‘Pied de Cuve’ [13,14,15,16]

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