Screening,identification, and preliminary characterization of yeast strains with brewing-related traits from Hovenia...

To identify suitable indigenous yeast strains for wine fermentation of Hovenia acerba Lindl., 74 initial isolates were recovered from naturally fermenting Hovenia acerba Lindl. must. Following morphological exclusion of non-yeast contaminants, 62 yeast-like isolates were grouped into morphotypes, and ten representative strains were selected for molecular identification and stepwise functional screening, evaluating gas production, ester formation, metabolic activity, and antagonistic activity against a sensitive indicator yeast strain (Saccharomyces cerevisiae NX 11424). This tiered screening strategy identified four high-performing candidate strains (WXJ-11, WXJ-13-2, WXJ-14-2, and WXJ-18-2) for comprehensive physiological tolerance and growth profiling on diverse carbon and nitrogen sources in modified media. Results revealed that all four candidates exhibited broad-spectrum physiological robustness, including tolerance to high sugar concentrations, low pH, elevated ethanol levels, high SO₂ concentrations, and extreme temperatures, as well as versatile growth potential on diverse carbon and nitrogen sources. Overall, under the screening conditions tested, their fermentation-related traits were either superior to or comparable with those of the commercial reference strain. In summary, the indigenous strains identified in this study expand the genetic resource pool of candidate yeasts for Hovenia acerba Lindl. wine fermentation. However, the screening assays employed are indirect and semi-quantitative, and all experiments were conducted in synthetic media under short-term conditions. Therefore, validation in whole Hovenia acerba Lindl. juice fermentation, combined with direct quantitative measurements of metabolic activity and aroma profiles, is required to confirm the industrial potential of these candidate strains.