Isolation, identification, and brewing characteristics analysis of yeast strains from Pyracantha fortuneana fruits fermentation liquid

Abstract

Pyracantha fortuneana (P. fortuneana) fruit, as a dual-purpose plant resource, is rich in nutrients; however, studies on the isolation and identification of yeast strains from P. fortuneana fruit and their brewing characteristics are scarce. To screen for high-quality yeast strains specifically for P. fortuneana wine from the fermentation liquid, this study employed traditional pure culture methods using WL nutrient agar for morphological identification of the isolated strains. Molecular biological identification of the yeasts was performed using molecular biology techniques. The brewing characteristics of the yeast strains were analyzed based on growth characteristics, sugar tolerance, alcohol tolerance, SO₂ tolerance, and acid tolerance, providing potential quality yeast resources for P. fortuneana wine production. The results indicated that a total of 12 yeast strains were isolated and purified. After identification, they were classified as Pichia kudriavzevii and Saccharomyces cerevisiae. Strain HJ-2 was able to grow normally under the conditions of 40°C, 15% alcohol by volume, 360 mg/L SO₂ mass concentration, pH 3.2, 400 g/L sucrose mass concentration, and 250 g/L glucose mass concentration. Strain HJ-6 exhibited normal growth under conditions of 40°C, 3% alcohol by volume, 360 mg/L SO₂ mass concentration, pH 3.2, 250 g/L sucrose mass concentration, and 300 g/L glucose mass concentration. Both strains HJ-2 and HJ-6 demonstrated strong ester production capability and low hydrogen sulfide production. Overall, strains HJ-2 and HJ-6 show potential for application in the industrial production of P. fortuneana wine.