Biodiversity and Winemaking Characteristics of Yeasts Isolated from Docynia delavayi (Franch.) Schneid. Wine Microbiota

The community of epibiotic yeasts significantly influences the quality of <i>Docynia delavayi</i> (Franch.) Schneid. wine. The yeast diversity in four different <i>Docynia delavayi</i> (Franch.) Schneid. wines during the brewing stage was investigated using pure culture methods and high-throughput sequencing technology. A total of 229,381,292 sequencing bases were generated, yielding 323,820 valid sequences with an average length of 708 nt and identifying 93 operational taxonomic units (OTUs) from naturally fermented samples of <i>Docynia delavayi</i> (Franch.) Schneid. wine for classification purposes. At the early fermentation stage, <i>Hanseniaspora</i> sp. was identified as the dominant species, whereas at the late fermentation stage, <i>Hanseniaspora</i> sp., <i>Saccharomyces</i> sp., and <i>Candida californica</i> became predominant. From these samples, a total of 109 yeast strains were isolated from <i>Docynia delavayi</i> (Franch.) Schneid. wine. Three specific strains-LZX-76, LZX-89, and LZX-104-were further selected based on their growth characteristics along with hydrogen sulfide production, ester production, ethanol production, and tolerance levels. Through morphological examination and molecular biology techniques, these strains were identified as <i>Pichia fermentans</i> and <i>Hanseniaspora</i> spp. Additionally, a total of 29 volatile compounds were detected through simulated fermentation processes; these included 12 esters, 6 alcohols, 2 acids, 4 aldehydes, and 5 other compounds. When compared to commercial yeasts used as starters in winemaking processes, it was observed that utilizing yeast strains LZX-76, LZX-89, and LZX-104 resulted in an increased number of volatile compounds, which enhanced the aromatic profile characteristics of <i>Docynia delavayi</i> (Franch.) Schneid. wine by making its aroma richer and more complex. The findings from this study hold significant potential value for both the production practices and research endeavors related to <i>Docynia delavayi</i> (Franch.) Schneid. wine.