Yeast species isolated from Texas High Plains vineyards and dynamics during spontaneous fermentations of Tempranillo grapes

Abstract

Vineyards and grape musts harbor complex locally specific microbial communities, among which yeast species can be responsible of spontaneous alcoholic fermentation. Although relying on indigenous yeast can be a risk for winemaking, local yeast diversity is associated with complexity and stronger identity of the wine produced, compared to inoculated alcoholic fermentation with commercial yeast strains. In this context, the main yeast species present on grapes, leaves and soils of Tempranillo and Cabernet Sauvignon vineyards in the hot semi-arid climate of the Texas High Plains area were investigated, as well as the presence and dynamics of yeast species during spontaneous fermentations of Tempranillo grapes from the same vineyards. Molecular characterization of yeast species was performed using culture-dependent 5.8S-ITS restriction fragment length polymorphism method and sequencing. Yeast species recovered from grapes, leaves, and soils were mainly dominated by Aureobasidium pullulans , Cryptococcus species, Filobasidium species and Naganishia species, typical members of the vineyard environment. One isolate of potential enological interest, Lachancea thermotolerans , a fermenting yeast with potential in must acidification, was recovered from the vineyard environment. However, spontaneous alcoholic fermentations revealed the presence of fermenting yeast species, including Saccharomyces cerevisiae , Lachancea thermotolerans and Hanseniaspora species. The presence of the three aforementioned species is of extreme interest for winemaking in the Texas High Plains area. Indeed, Saccharomyces cerevisiae is the model for alcoholic fermentation, Hanseniaspora species have been shown to improve palatability of wines, and Lachancea thermotolerans has become of increasing interest due to its potential to acidify musts and palatability. One of the main characteristics of grapes grown in the Texas High Plains area being the lack of acidity, focusing on these three yeast species could promote the development of locally oriented started cultures for the production of wines with a stronger local identity.

Control of Penicillium glabrum by Indigenous Antagonistic Yeast from Vineyards

“…Settanni et al [57] reported high counts of yeasts in grapes from the Marsala wine area (Italy) with values that ranged from 3.54 to 6.92 log 10 CFU/g, which agreed with the yeast population found in the present work. In contrast, lower counts (10 2 to 10 4 log 10 CFU/g) of yeasts in healthy grapes from Texas (USA) were reported by Bougreau et al [58]. Damaged grapes gave higher counts of yeasts than healthy grapes from Attica (Greece), according to Nisiotou and Nychas [59] and from Trento, Italy [60]; these are in contrast with the results obtained in the present work.…”

Capturing yeast associated with grapes and spontaneous fermentations of the Negro Saurí minority variety from an experimental vineyard near León

“…This study aligns with the increasing demand for indigenous S. cerevisiae isolates that are representative of a specific oenological area 62 , with particular wineries increasingly selecting yeasts within their vineyard for specific characteristics and suitability to local grape varieties 63,64 . Extensive studies of spontaneous fermentations in Italy 65 , Spain 18,66 , USA 67 and Canada 68 (including studies specifically of the genetic diversity of Saccharomyces cerevisiae in different wine-producing regions 36,69,70 ) are validated or partly motivated by reports 71 www.nature.com/scientificreports/ of a significant correlation between the region from where the strains were isolated and the aroma profile of the resulting wines. In this study, four non-Saccharomyces yeasts (Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora uvarum and Torulaspora delbrueckii) were isolated from Negro Saurí grapes and must, based on their colony morphology and subsequent ITS sequencing.…”

Characterization of Old Wine Yeasts Kept for Decades under a Zero-Emission Maintenance Regime

“…The strive for more volatile aromas has spurred the search for alternative yeasts and renewed the interest in spontaneous fermentations [26]. Yet, due to the unpredictable and inconsistent outcomes of spontaneous fermentations, the development of improved starter cultures or consortia may provide better alternatives [27,28].…”