Association between Grape Yeast Communities and the Vineyard Ecosystems

Area of Science:

• Microbiology
• Oenology
• Agricultural Science

Background:

• Grape yeast biota plays a crucial role in wine fermentation and contributes to wine's unique characteristics.
• Understanding yeast community composition is essential for wine typicity and quality.
• The Azores Archipelago, with its diverse microclimates and soils, presents a unique ecosystem for studying grape yeast biogeography.

Purpose of the Study:

• To assess the grape yeast biota across distinct wine-producing areas in the Azores.
• To explore differences in yeast community composition related to geographic origin, soil types, and grapevine training systems.
• To investigate the relationship between grape yeast communities and wine typicality in unique viticultural terroirs.

Main Methods:

• Collected 57 grape samples from Vitis vinifera cultivars (Verdelho, Arinto, Terrantez) over two years.
• Performed 40 spontaneous fermentations.
• Isolated and identified 1710 yeast strains from grapes and 1200 from fermentations using microbiological techniques.

Main Results:

• Identified 28 yeast species, with Hanseniaspora uvarum, Pichia terricola, and Metschnikowia pulcherrima being most abundant.
• Candida carpophila was newly identified in grape-associated environments.
• Observed higher proportions of H. uvarum in Verdelho grapes compared to Arinto.
• Found significant qualitative differences in yeast communities across various locations and islands, linked to agro-ecological factors.

Conclusions:

• Grape yeast biogeography is non-randomly influenced by climate, soil, cultivar, and vine training systems.
• Distinct viticultural terroirs harbor unique yeast biota.
• These findings support a strong link between grape yeast communities and the typicality of wines produced in specific regions.