 IVES 9 IVES Conference Series 9 Exploring the resistance of non-Saccharomyces wine yeasts to dehydration-rehydration processes

Exploring the resistance of non-Saccharomyces wine yeasts to dehydration-rehydration processes

Abstract

AIM: The use of non-Saccharomyces (NS) yeasts in multi-starter fermentations with S. cerevisiae is a trend in the wine industry, but the number of strains commercially available in a powder formulation, such as active dry yeasts (ADY), is still limited. Considering that NS strains are bioresources which could boost innovation in the wine sector, efficient production of powder formulations is of utmost importance to valorise bioresources outside the laboratory environment.

METHODS: Three strains with high oenological potential, selected in previous studies, namely Lachancea thermotolerans DBT027, Metschnikowia sp. DBT012 and Starmerella bacillaris DBT045 were grown in a sterilized medium mainly constituted by grape juice with yeast assimilable nitrogen integration. Early stationary growth phase cultures were collected and suspended in 1% yeast extract, for powder production. The three prototype batches were rehydrated in tap water, to mimic winery conditions, for 15 minutes at four temperatures (20, 25, 30 and 35 ºC). Survival rates of yeasts were assessed before and after rehydration, and after storage at -20 ºC. The same powder NS yeasts were also in multi-starter fermentations in winery and their persistence was monitored.

RESULTS: The selected NS yeast strains were able to grow in the production medium with similar yields, and the powder formulation retained elevated cell viability (around 109-1010 cells/g). The optimal rehydration temperature was different for the three strains: Metschnikowia sp. DBT012 and L. thermotolerans DBT027 maintained higher survival at 35 ºC, while S. bacillaris DBT045 at 20 ºC, as could be expected considering the phenotypic characteristics of the species. Technological performances of the tested powder formulations were satisfactory, especially for DBT012, which was able to grow in grape must after inoculation and dominated over the indigenous microbiota.

CONCLUSIONS

The applied protocol for producing NS yeasts in the powder formulation was successful, as they retained high viability during rehydration and suitable activity when inoculated in must. Powder formulation guaranteed the conservation of the same batch for several comparative tests, bringing out their positive contribution to innovative winemaking biotechnologies. The ability to withstand a larger scale process of biomass production is essential for the exploitation of suitable non-Saccharomyces yeasts selected among a collection of yeast strains with proven oenological potential at laboratory scale. ACKNOWLEDGMENTS: Research developed in the framework of POR FESR 2014-2020 Regione del Veneto, project VIT-VIVE

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Giovanna Felis

Department of Biotechnology, University of Verona, Italy,Renato Leal BINATI, Dept. Biotechnology, University of Verona, Italy Eleonora TROIANO, Dept. Biotechnology, University of Verona, Italy Sandra TORRIANI, Dept. Biotechnology, University of Verona, Italy Marta TEBALDI, Microbion S.r.L. Italy Alessandro RONCADOR, Microbion S.r.L. Italy Fabio FRACCHETTI, Microbion S.r.L. Italy

Contact the author

Keywords

starter cultures, biomass production, dehydration, active dry yeasts

Citation

Soil incorporation of new superabsorbent hydrogels to improve vine tolerance to summer stress: physiological validation and vineyard applications

Hydrogels are soil-conditioning materials capable of absorbing substantial amounts of water relative to their weight.

Grape and wine quality of terraced local variety Pinela (Vitis vinifera L.) under different water management

Climate change is driving global temperatures up together with a reduction of rainfall, posing a risk to grape yields, wine quality, and threatening the historical viticulture areas of Europe.

Selecting green cover species in the under-trellis zone of Lower Austrian vineyards

The under-trellis zone of vineyards is a sensitive area through which vines cover a significant portion of their nutrient and water needs. Mechanical and chemical methods are applied to suppress competing and tall-growing weeds to ensure optimal vine growth conditions. In addition to higher operating costs and depending on the soil conditions, these practices might lead to a long-term reduction in soil fertility and biodiversity. The presented study aims to analyse the suitability and interspecies competition of a selected green cover mixture of five local herbaceous species as potential green cover mixture in the under-trellis area of Lower Austrian vineyards.

Histoire des Vitis depuis leurs origines possibles sur la Pangée jusqu’aux cépages cultivés : un exemple de résilience liée à la biodiversité des espèces

The first forms of life on earth were bacteria and single-celled blue-green algae. They evolved into land plants around 500 million years ago, developing mechanisms for surviving on land, such as roots, stems and leaves. This evolution also led them to coexist with other organisms, such as insects and animals, for pollination and seed dispersal, as well as to resist environmental factors such as drought and disease.

Meso-scale geostatistical analysis: a method for improving experimental design

The growing region of Barolo DOCG certified wines is topographically complex. The region is famous for this complexity and for the associated terroir driven Nebbiolo grapes and wines derived distinctly from this varietal. Although it is recognized that the Barolo area is unusual topographically and it is assumed that this unusual topography lends to the inherit terroir, the specifics of this relationship are less well defined.