Enhancing Ethanol Tolerance via the Mutational Breeding of Pichia terricola H5 to Improve the Flavor Profiles of Wine

Although using non-Saccharomyces yeasts during alcoholic fermentation can improve the wine aroma, most of them are not ethanol tolerant; therefore, in 2017, this study screened 85 isolated and identified from 24 vineyards seven Chinese wine-producing regions, obtaining Pichia terricola strain H5, which displayed 8% tolerance. Strain H5 was subjected to ultraviolet (UV) irradiation diethyl sulfate (DES) mutagenesis treatment obtain mutant strains with different characteristics parental H5. Compared UV-irradiated strains, UV5 UV8, showed significantly higher tolerance capacity. Modified aroma profiles were also evident samples exposed mutants. Increased ethyl caprate, caprylate, dodecanoate content apparent samples, providing a distinctly floral, fruity, spicy profile. Fermentation UV8 produced high acetate concentration, causing present highly unpleasant odor. To certain extent, UV improved ability changing This provides theoretical basis for industrial application that flavor.