A total of 19 yeasts were isolated in the process of identifying the optimum starter cultures for the production of fruit wine. Three strains were chosen from among these isolates, purified, and evaluated for their ability to ferment grapefruit juice. In pure cultures, three yeast strains (S1, S2, and S3) that were separated from grapefruits were examined for their ability to produce fruit wine. The impact of starting pH on growth, growth capacity in the presence of ethanol, biomass evolution, and the physicochemical characteristics of the resulting wines were all ascertained. The 18S ribosomal DNA gene sequencing indicates that the two isolated strains (S1 and S3) are members of the species Debaryomyces nepalensis (96.34%) and Candida tropicalis (98.49%), respectively. The results showed that the (S1) and (S3) starters showed the best fermentation power with a remarkable production of the alcohol content which is 11.63 (%v/v) and 11.4 (%v/v) respectively, while a decrease in the specific density and the soluble solids rate was observed in a minimum time of (144 h). All starters had the ability to grow under acidic (3, 4, 5, 6) and basic (8) pH conditions, but the highest growth was between pH (3-4). A decrease in growth is recorded for all strains above 16 (%v/v) of ethanol. However, these decreases vary by strain. Culture with strain (S2) is the medium where the greatest decrease is observed, regardless of the ethanol content. The temperatures at which these sourdoughs could grow were 25 °C, 30 °C, and 35 °C. At 30 °C, the highest growth was recorded. Lastly, for the (S1) and (S3) yeast strains used for the wine production trial, the ideal growth conditions in terms of temperature, Brix, and pH were 30 °C, 30°B, and 3-4, respectively.