Macrowine 2021
IVES 9 IVES Conference Series 9 Improvement of non-Saccharomyces yeast dominance during must fermentation by using spontaneous mutants resistant to SO2, EtOH and high pressure of CO2

Improvement of non-Saccharomyces yeast dominance during must fermentation by using spontaneous mutants resistant to SO2, EtOH and high pressure of CO2

Abstract

AIM: A genetic study of four wine T. delbrueckii strains was done. Spore clones free of possible recessive growth‐retarding alleles with enhanced resistance to winemaking stressing conditions were obtained from these yeasts.

METHODS: The genetic marker of resistance to cycloheximide (cyhR) allows easy monitoring of the new mutants obtained from these yeasts. Identity of the high pressure resistant (HPR) mutants was verified by analysis of cell morphology, killer phenotype, cyhR marker, presence of viral dsRNA, RFLPs of mtDNA, and sequencing of Internal Transcribed Spacer ofribosomal DNA (ITS).

RESULTS: T. Delbrueckii mutants were isolated from some spore clones. Papillae resistant to SO2 were isolated. Subsequently, new spontaneous mutants capable of growing on YEPD plates with 10% ethanol were isolated. Rosé sparkling wine (cava) was made using these mutants. Two mutants, with the best fermentation kinetics and closest to the reference yeast Sc 85R4, were isolated from some bottles with high CO2 pressure and some were selected there after (Td MutHP41 and Td MutHP42). They had better fermentation kinetics and dominance than their parental yeast. Td MutHP41 showed great improvement for industrial base wine fermentation with respect to its parental yeast. Re-isolation and selection procedure to obtain new reinforced HPR mutants from previously selected HPR mutants was not a sound strategy to continue improving the fermentative capability of T. delbrueckii under high CO2 pressure. Continuous shaking during inocula preparation further improved the fermentative capability of T. delbrueckii yeasts.

CONCLUSIONS: Isolation of spontaneous mutants resistant to SO2 and ethanol seems to be a good strategy to slightly improve the fermentative efficiency of T. delbrueckii in must and base wine. The new mutants were genetically stable enough to be considered for industrial production, and their fermentative capability was further improved by continuously supplying oxygen during the conditioning stage before yeast culture inoculation in base wine.

DOI:

Publication date: September 10, 2021

Issue: Macrowine 2021

Type: Article

Authors

Alberto Martínez Brígido 1, Rocío Velázquez 1, Joaquín Bautista-Gallego 1, Emiliano Zamora 2, Manuel Ramírez 1

1 Departamento de Ciencias Biomédicas, Universidad de Extremadura, 06006 Badajoz, Spain.
2 Estación Enológica, Junta de Extremadura. 

Contact the author

Keywords

Torulaspora delbrueckii; wine fermentation, sporeclone; sparkling wine; ethanol resistance; SO2 resistance; pressure resistance

Citation

Related articles…

Variety “Rebula” (Vitis vinifera L.) determines the terroir Goriška brda “Collio” in Slovenia

A «terroir» is a group of vineyards from the same region, belonging to a specific appellation, and sharing the same type of soil, weather conditions, grapes and wine making savoir-faire, which contribute its specific personality to the wine. White wine variety «Rebula» or «Ribolla gialla» is a local and traditional variety, which is mentioned already in XIII. century like variety for tax paying and merchandise.

Read More

137Cs analysis by gamma spectrometry and its potential for dating Portuguese old wines

Analytical methods for dating wines often rely on assessing anthropogenic and cosmogenic radionuclides, including 14C and 137Cs [1,2].

Read More

Paysages viticoles et terroir dans l’OAC Ribeira Sacra (Galice, NO de l’Espagne)

The concept of Appellation d’Origine Contrôlée (AOC) is based on the existence of a link between the characteristics of the terroir and the quality and typicality of the production (DELAS, 2000). If for a long time, this link only appeared as the fruit of empiricism, the research undertaken recently has made it possible to scientifically establish the complex relationships between the functioning of natural environments and the ability to produce quality.

Read More

Pruning vine-shoots as a new enological additive to differentiate and improve the quality of wines

The objective of these work was to demonstrate that toasted fragments of pruning vine-shoots added to the wines after fermentation provide them with differentiated aromatic notes and improve their quality.

Read More

Estimation of degree brix in grapes by proximal hyperspectral sensing and nanosatellite imagery through the random forest regressor

The assessment of physiological parameters in vineyards can be done by direct measurements or by remote, indirect methods. The latter option frequently yields useful data, and development of methods and techniques that make them possible is worthwhile. One of the parameters most looked for to define the quality status of a vineyard is the degree Brix of its grapes, a quantity usually determined by direct measurement.

Read More