WAC 2022 banner
IVES 9 IVES Conference Series 9 WAC 9 WAC 2022 9 3 - WAC - Posters 9 Assessment of O2 consumption, a new tool to select bioprotection yeast strains

Assessment of O2 consumption, a new tool to select bioprotection yeast strains

Abstract

Reduction of sulfur dioxide during winemaking is a request from the wine industry. To replace sulfur dioxide, various alternatives exist, including bioprotection by yeast inoculation. This practice consists in adding non-Saccharomyces yeasts directly on the grapes or must. The antimicrobial properties of non-Saccharomyces yeasts have already been demonstrated due a to niche occupation of the grape must, resulting in a decrease of fungal and acetic bacteria communities. Furthermore, their potential antioxidant properties by consuming oxygen hence reducing the browning of the must and maintaining GSH concentration in white wines has also been described. However, only a few strains of two non-Saccharomyces species were considered in the previous studies while it is known that a significant intra-species genetic diversity exists [1]. In this study, inter and intra species diversity were considered to evaluate O2 consumption by yeast during the prefermentary steps.

First, laboratory assays were optimized and various technological parameters were analyzed such as the O2 concentration, the physiological state of yeasts, the yeast dosages and mixed-combination. Subsequently, 47 yeast strains distributed over 6 enological species and representing their genetic diversity were selected. In order to measure on line dissolved oxygen, a compact FireStingO2 oximeter (Pyroscience, Aix-La-Chappelle, Germany) was used. The kinetics of O2 consumption by yeast in a grape must model medium were evaluated and the consumption rates were calculated and expressed as mg of O2 consumed per liter and per number of living cells (determined by flow cytometry). Thus, an Oxygen Consumption Rate (OCR) per strain was obtained, ranging from 15 to 65 mg/L.

Results show that an interspecific diversity can be highlighted. Indeed, some species consumed significantly more O2 than others. The O2 consumption in grape must by yeasts could be linked to their respiratory metabolism and correlated with a Crabtree effect. Moreover, for some species, intraspecific diversity was obtained revealing a variability which could be interesting to further investigate. These results provide important data for selecting new bioprotection strains in winemaking.

References

1.Masneuf-Pomarede, I.; Bely, M.; Marullo, P.; Albertin, W. The Genetics of Non-Conventional Wine Yeasts: Current Knowledge and Future Challenges. Frontiers in microbiology 2016, 6, 1563.

DOI:

Publication date: June 27, 2022

Issue: WAC 2022

Type: Article

Authors

Claudia Nioi, Joana Coulon, Isabelle Masneuf-Pomarède,

Presenting author

Sara Windholtz – Univ. Bordeaux, INRAE, Bordeaux INP, UR OENOLOGIE, EA 4577, USC 1366, ISVV, F-33140 Villenave d’Ornon, France

Univ. Bordeaux, INRAE, Bordeaux INP, UR OENOLOGIE, EA 4577, USC 1366, ISVV, F-33140 Villenave d’Ornon France, | Biolaffort, 11 Rue Aristide Bergès, 33270 Floirac, France, | Bordeaux Sciences Agro, 33170 Gradignan, France – Univ. Bordeaux, INRAE, Bordeaux INP, UR OENOLOGIE, EA 4577, USC 1366, ISVV, F-33140 Villenave d’Ornon France

Contact the author

Keywords

O2 consumption – bioprotection – SO2 alternative- non-Saccharomyces yeasts

Tags

IVES Conference Series | WAC 2022

Citation

Related articles…

Rapid optical method for tannins estimation in red wines

In this work, an innovative analytical method has been proposed for fast and reliable in-line analysis of tannins in wines; the method is fast, does not require sample preparation and is based on the selective reactivity of tannins in a mixture containing proteinaceous matter (i.e. gelatin), under pH 3.5, resulting in the formation of white cloudiness.

INFLUENCE OF THE THICKNESS OF OAK ALTERNATIVES ON THE COMPOSITION AND QUALITY OF RED WINES

Aging red wines in oak barrels is an expensive and laborious process that can only be applied to wines with a certain added value. For this reason, the use of oak alternatives coupled with micro-oxygenation has progressively increased over recent years, because it can reproduce the processes taking place in the barrels more economically and quickly [1]. Several studies have explored how oak alternatives [2-5] can contribute to wine composition and quality but little is known about the influence of their thickness.

Traditional agroforestry vineyards, sources of inspiration for the agroecological transition of viticulture

A unique “terroir” can be found in southern Bolivia, which combines the specific features of climate, topography and altitude of high valleys, with the management of grapevines staked on trees. It is one of the rare remnants of agroforestry viticulture. A survey was carried out among 29 grapegrowers in three valleys, to characterize the structure and management of these vineyards, and identify the services they expect from trees. Farms were small (2.2 ha on average) and 85% of vineyards were less than 1 ha. Viticulture was associated with vegetable, fruit and fodder production, sometimes in the same fields. Molle trees were found in all plots, together with one or two other native tree species. Traditional grapevine varieties such as Negra Criolla, Moscatel de Alejandría and Vicchoqueña were grown with a large range of densities from 1550 to 9500 vines ha-1. From 18 to 30% of them were staked on trees, with 1.2 to 4.9 vines per tree. The management of these vineyards (irrigation, fertilization and grapevine protection) was described, the most particular technical operation being the coordinated pruning of trees and grapevines. Three types of management could be identified in the three valleys. Grapegrowers had a clear idea of the ecosystem services they expected from trees in their vineyards. The main one was protection against climate hazards (hail, frost, flood). Then they expected benefits in terms of pest and disease control, improvement of soil fertility and resulting yield. At last, some producers claimed that tree-staking was quicker and cheaper than conventional trellising. It can be hypothesized then that agroforestry is a promising technique for the agroecological transition of viticulture. Its contribution to the “terroir” of the high valleys of southern Bolivia and its link with the specificities of the wines and spirits produced there remain to be explored.

TerraClim, an online spatial decision support system for the wine industry

Climate projections for the future suggest favourable conditions for some wine producing regions, but challenging conditions for others. For instance, temperature increases are likely to shift grapevine phenology, ripening and harvest dates, and potentially affect grape quality and yield.

Impact of glutathione and elemental sulphur juice addition on the volatile thiol production in South African Sauvignon blanc wine

Three compounds, 3-mercaptohexanol (3MH), 3-mercaptohexyl-acetate (3MHA) and 4-mercapto-4-methylpentan-2-one (4MMP), also known as varietal thiols, have been identified to contribute positively to wine aroma and are responsible for the distinct gooseberry, grapefruit, guava and box tree character found in Sauvignon blanc wines. Certain volatile thiol compounds though, can cause off-aromas of onion, garlic, rubber and rotten egg, this group of molecules is known as reductive sulphur compounds (RSC). This study looks into how the addition of sulphur-compounds to Sauvignon blanc juice contributes to the varietal thiol (3MH and 3MHA) concentration and reductive sulphur compound concentration in South African Sauvignon blanc wine.