Persistence of Two Non-Saccharomyces Yeasts (Hanseniaspora and Starmerella) in the Cellar

Abstract

Different genera and/or species of yeasts present on grape berries, in musts and wines are widely described. Nevertheless, the community of non-Saccharomyces yeasts present in the cellar is still given little attention. Thus it is not known if the cellar is a real ecological niche for these yeasts or if it is merely a transient habitat for populations brought in by grape berries during the winemaking period. This study focused on three species of non-Saccharomyces yeasts commonly encountered during vinification: Starmerella bacillaris (synonymy with Candida zemplinina), Hanseniaspora guilliermondii and Hanseniaspora uvarum. More than 1200 isolates were identified at the strain level by FT-IR spectroscopy (207 different FTIR strain pattern). Only a small proportion of non-Saccharomyces yeasts present in musts came directly from grape berries for the three species studied. Some strains were found in the must in two consecutive years and some of them were also found in the cellar environment before the arrival of the harvest of second vintage. This study demonstrates for the first time the persistence of non-Saccharomyces yeast strains from year to year in the cellar. Sulfur dioxide can affect yeast populations in the must and therefore their persistence in the cellar environment.

Keywords: Hanseniaspora; Starmerella; cellar; non-Saccharomyces strains; persistence.

FIGURE 1

Percentage of Starmerella bacillaris (A), Hanseniaspora guilliermondii (B) and H. uvarum (C) isolated from berries (T berries, T enrich), grape must (T0d) and during alcoholic fermentation (T3d, T6d, T9d, Tf) without () and with SO₂ () for 2012 vintage. These percentages correspond to yeast belonging to the respective species compared to the total number of yeast isolates in the corresponding sample time.

FIGURE 2

Distribution of Starmerella bacillaris strain patterns during 2012 vintage isolated on berries (T enrich), in grape must (T0d) and during alcoholic fermentation (T3d, T6d, T9d, Tf) without SO₂ (A) and with SO₂ (B). No strain pattern was detected on grape berries without enrichment step.

FIGURE 3

Repartition of H. guilliermondii strain patterns isolated on berries, in grape must, during alcoholic fermentation (T3d, T6d, T9d, Tf) with and without SO₂ for 2012 and 2013 vintages and in cellar environment in 2013 before the arrival of harvest. Numbers on the top of the barplot correspond to the number of different strain patterns. The term “other” includes the strain patterns which were detected once.

FIGURE 4

Repartition of H. uvarum strain patterns isolated on berries, in grape must, during alcoholic fermentation (T3d, T6d, T9d, Tf) with and without SO₂ for 2012 and 2013 vintages and in cellar environment in 2013 before the arrival of the harvest. Numbers on the top of the barplot correspond to the number of different strain patterns. The term “other” includes the strain patterns which were detected once.