Fan Mingtao

Assessment of β-D-glucosidase activity of intact cells of two Oenococcus oeni strains with synthetic and natural substrates.

Li Y., Ma Y., Fan M., Huang K., Zhang H. (2016): Assessment of β-d-glucosidase activity of intact cells of two Oenococcus oeni strains with synthetic and natural substrates. Czech J. Food Sci., 34: 16–23. The β-d-glucosidase (βG) activity of intact cells of Oenococcus oeni SD-2a and 31MBR was assessed with synthetic and natural substrates, also its partial characterisation was investigated. Results showed that intact cells of both strains showed βG activity, SD-2a performing higher than 31MBR, against either synthetic or natural substrate. The high βG activity of SD-2a intact cells under wine-like temperature, pH, ethanol concentration, and glucose concentration could be of great interest for its utilisation in winemaking. SD-2a proved promising for aroma enrichment in winemaking.

Influence of abiotic stress on β-D-glucosidase activity of two typical Oenococcus oeni strains in China

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.