Yeast Diversity during Spontaneous Fermentations and Oenological Characterisation of Indigenous for Potential as Wine Starter Cultures.

Diversity of regional yeast can be influenced by geography, grape cultivars and the use of SO, but at single vineyard scale in China, the impact of these factors on yeast population, particularly is not well studied. Here, we characterised yeast species and dynamics during spontaneous fermentations with/without SO using eight typical grape cultivars from Yuma vineyard in Ningxia wine region of China. Results show that distribution and abundance of yeast species varied by grape varieties, fermentation stage and SO treatment. A number of 290 isolates were further classified into 33 genotypes by Interdelta fingerprinting. A prevailing role of grape varieties in shaping the genetic divergence of in Yuma vineyard was observed, as compared to the impacts of fermentation stage and SO treatment. Pre-selected strains were subjected to vinification with Cabernet Sauvignon and Chardonnay. All strains completed fermentations but the physiochemical parameters and volatile profiles of wines were strain-specific. Some indigenous yielded more desirable aroma compounds compared to the commercial strains, among which NX16 and NX18 outcompeted others, therefore having potential for use as starters. This study provides comprehensive analysis on yeast diversity at vineyard scale in Ningxia. Information on the vinification using indigenous is of great value for improving Ningxia wine regionality.