Isolation，Identification and Enzymatic Characteristics of Yeasts Producing β-Glucosidase

Abstract:

During the fermentation of wine under natural conditions，non-Saccharomyces yeasts predominate in the initial stage of fermentation，and they can produce the unique hydrolytic activity β-glucosidases which give the wine a special aroma. In this study，a strain with good capacity of producing β-glucosidase was isolated from must by the collection and screening of non-Saccharomyces yeasts during the fermentation of Xinjiang Cabernet. The strain was indentified as Pichia kluyver and named P. kluyveri XYN086 by morphology and ITS sequence analysis. The studies on enzymatic properties showed that the optimum pH for the β-glucosidase was 6.0 and its activity remained at more than 60% in pH 6.0-8.0. Furthermore，the optimum temperature for this enzyme was 60 ℃ and its activity was kept better at this temperature. Metal ions has a great influence on the activity of β-glucosidase，the enzyme was activated by Fe2+ and Cu2+，whereas it was inhibited by Mg2+，Ca2+，K+，and Na+. These results showed that XYN086 had the potential development values of producing β-glucosidase.