Abstract:

The wine-related lactic acid bacteria, especially Oenococcus oeni, can produce glycosidase and release volatile
aroma compounds through hydrolysis of grape-derived aroma precursors by undertaking malolactic fermentation (MLF),
thus improving the aroma complexity of the wine. To investigate five glycosidase activities, 19 strains of O. oeni from
five wine-producing regions in China and a commercial strain were selected, and then five strains with higher glycosidase
activities were used to explore glycosidase properties in model wine environment. The results showed that all these 20
strains produced detectable glycosidase activities towards the corresponding substrates. Significant differences were
observed among different strains, while no difference was observed among different wine regions. The optimum pH was
4.0 and optimum temperature was 45 ℃ for glycosidase. Ethanol and fructose could stimulate at lower concentrations (4%
ethanol ＋ 0.1 g/100 mL fructose) but significantly inhibit at higher concentrations (14% ethanol ＋ 2 g/100 mL fructose)
glycosidase activity, which, however, was inhibited by glucose at all investigated concentrations. Furthermore, the responses
of the enzyme activities were strain-dependent. In the model wine environment, only 9.805%-32.331% of glycosidase activity
remained. In conclusion, SD-1f displayed the highest glycosidase activity among all selected strains.

Key words: wine, Oenococcus oeni, glycosidase activity