Abstract

Richard Lim, Yang Lee and Feng Yamaha

β-D-Glucosidase is one of the most interesting glycosidases for hydrolysis of glycoconjugated precursors to release active aromatic compounds in musts and wines. SD-2a and 31MBR are two typical Oenococcus oeni strains widely used in winemaking in China. Up to now, there is still limited information regarding the β-D-glucosidase activity of the two strains. β-D-Glucosidase activity of the two strains was localized and influence of abiotic stress on the enzyme activity was conducted using synthetic substrate in the present study. Both SD-2a and 31MBR possessed β-D-glucosidase activity, activity occurring in whole cells and permeabilized cells but not in the culture supernatant. Whole cells of SD-2a showed higher enzyme activity than that of 31MBR, while 31MBR exhibited higher permeabilized cells activity. β-D-Glucosidase from the two strains remained high activity after both bacteria were stressed under winelike conditions for two hours, however, activity decreased sharply when the bacteria were stressed at 45°C, pH 2.5 or ethanol concentration of 16%. SD-2a proved potential for aroma improvement in winemaking, as the whole cells showed high β-D-glucosidase activity under winelike conditions.