Mycobiota consortium in wine fermentation

Abstract

The creation of interspecific hybrid varieties (IHVs) with resistance to diseases such as powdery mildew and downy mildew has made it possible to reduce the use of inputs within vineyards. In this context, IHVs respond to societal demands for minimizing environmental impact and are increasingly being adopted in viticulture [1,2]. At the same time, wines produced through spontaneous fermentation, which rely on native berry microbiota, have recently gained popularity. It is therefore important to understand the particularities of spontaneous fermentation in the context of IHVs [3]. To this end, micro-fermentations were performed using the microbiota of Carignan (a traditional grape) and Artaban (an IHV). The microbiota composition of each variety was analyzed by metabarcoding and then used to inoculate flash-pasteurized must, either by microbiota transplantation through berry rinsing or pied-de-cuve, or using a yeast starter. We then investigated the feasibility of replicating indigenous fermentations using an artificial yeast consortium. Based on the characterization of the microbiota, the proportions of different yeast species were estimated, and artificial consortia were assembled using purified strains isolated from grapes or must. These consortia were then used to inoculate the same flash-pasteurized must, allowing fermentations to take place under identical conditions. Fermentation kinetics, physico-chemical changes in the must, and the composition of fermentative aromas in the resulting wines were compared with data obtained from the natural microbiota.

Funding

G.P.-M. thanks the Occitanie region and the INRAE MetaBio metaprogram for funding her PhD.

References

[1] Delmotte, F., Fabre, F., Miclot, A.S., Paineau, M., Schneider, C., et al. Des vignes, des invasions et des résistances (2021).

[2] Guimier, S., et al. OSCAR, a national observatory to support the durable deployment of disease-resistant grapevine cultivars. XII International Conference on Grapevine Breeding and Genetics, 1248, 21–34 (2018).

[3] Padilla, B., Gil, J.V., & Manzanares, P. Past and future of non-Saccharomyces yeasts: from spoilage microorganisms to biotechnological tools for improving wine aroma complexity. Frontiers in Microbiology, 7 (2016).