Investigation of the Fermentation Characteristics of Yeast in the Natural Fermentation Solution Derived from...

Passiflora edulis (P. edulis Sims) is prevalent in tropical regions, and its distinctive taste and aroma are highly appreciated due to its unique nutritional profile. With the increasing recognition of the added value of P. edulis Sims wine, an expanding number of researchers have begun to focus on the related studies concerning the brewing process of this wine. Isolating high-quality yeast strains from the natural fermentation broth of P. edulis Sims is crucial for this purpose. In this study, 38 yeast strains were isolated and purified from the fermentation broth of P. edulis Sims. Nine yeast strains were selected using WL medium for further analysis. The fermentation characteristics of these strains were evaluated based on their production of esters, ethanol, and hydrogen sulfide (H₂S), as well as through tolerance tests. The results indicated that the nine yeast strains exhibited favorable fermentation performance characterized by low H₂S production while demonstrating high levels of ester and ethanol production, along with certain antimicrobial activity. Among these strains, GZH-20 displayed a notably low capacity for H₂S production coupled with exceptional abilities in both ester and ethanol generation. Furthermore, this strain demonstrated good tolerance under various conditions, including pH levels ranging from 2.8 to 3.8, a glucose concentration of 200 g/L, and varying sulfur dioxide (SO₂) concentrations between 60 g/L and 360 g/L; it showed superior capacities for producing esters and ethanol under these conditions. Molecular identification confirmed that this strain is classified as Wickerhamomyces anomalus. These findings hold significant implications for advancing our understanding of specialized yeasts involved in P. edulis Sims wine production.