[P003] Poster

12:10 PM - 1:00 PM JST(3:10 AM - 4:00 AM UTC)

[P02-161] Indigenous Yeast Diversity on Wine Grapes from Japanese Vineyards and Enological Characteristics of Saccharomyces cerevisiae

○Misa Otoguro¹, Kaito Shibayama¹ (1. The Institute of Enology and Viticulture, University of Yamanashi (Japan))

Keywords:

Indigenous yeast diversity,wine grape,Saccharomyces cerevisiae

[Purpose]
Japan has numerous vineyards with diverse geographical and climatic conditions, which may influence the composition of indigenous microbial communities associated with wine grapes. Although yeasts play a crucial role in wine fermentation and can contribute to regional wine characteristics, the diversity of yeasts associated with wine grapes in Japan has not yet been comprehensively investigated. The aim of this study was to characterize the diversity of yeasts present on wine grapes collected from four wine-producing regions in Japan and to evaluate the enological potential of indigenous Saccharomyces cerevisiae strains isolated from two of these regions.
[Method]
A total of 17 wine grape samples were collected from four wine-producing regions in Japan. From these samples, 3,066 yeast strains were isolated. The isolates were identified using MALDI-TOF MS and 26S rDNA sequence analysis. The distribution of yeast species among grape varieties and regions was analyzed to evaluate differences in yeast communities. In addition, indigenous S. cerevisiae strains isolated from two regions were genotyped and characterized for their physiological properties. Fermentation experiments were also conducted to evaluate their enological potential. Mixed fermentations were performed using combinations of indigenous S. cerevisiae strains with Starmerella bacillaris or Hanseniaspora vineae. The physicochemical characteristics of the resulting wines, including organic acid composition, were compared with those of wines produced using commercial yeast strains.
[Results]
Among the 3,066 isolates obtained from the grape samples, 26 non-Saccharomyces species and one Saccharomyces species (S. cerevisiae) were identified. Non-Saccharomyces yeasts were abundant and widely distributed among the grape samples. Differences in yeast species distribution were observed among grape varieties and regions, suggesting that local environmental conditions influence the composition of yeast communities on wine grapes. Indigenous S. cerevisiae strains isolated from different regions exhibited distinct genotypes and physiological characteristics. In fermentation experiments, wines produced with indigenous yeast strains showed differences in organic acid profiles compared with wines fermented with commercial yeast strains. These results indicate that indigenous yeasts may influence wine composition and potentially contribute to regional wine characteristics.
[Consideration]
The diversity and distribution patterns of yeasts observed in this study suggest that vineyards in different regions harbor distinct indigenous yeast communities. Furthermore, the physiological diversity of indigenous S. cerevisiae strains and their interactions with non-Saccharomyces yeasts during mixed fermentation may affect the chemical composition of wines. Such microbial diversity may therefore play an important role in shaping regional wine styles.
[Conclusion]
This study provides new insights into the diversity of indigenous yeasts associated with wine grapes in Japan. The results highlight the potential of local yeast strains for the development of starter cultures that may impart region-specific organoleptic characteristics to wines produced in Japan. Further studies will be required to fully evaluate the enological properties and practical applications of these indigenous yeast strains.