Characterization of Oenococcus oeni for the production of b-glucosidase, esterase and protease activity.

The production of extra cellular hydrolytic activities by O. oeni may have an impact on wine quality.he -glucosidase, esterase and protease activity of 31 O. oeni strains was studied. The enzymatic activity of the culture supernatant fluid and intact cells was assayed using fluorimetric methods. -glucosidase activity was measured as the amount of 4- metilumbeliferone (4-MU) released from 4-metilumbelliferil D-glucopiranoside (4-MUG) as substrate. Esterase activity was measured as the amount of 5(6)-carboxyfluorescein (cF) released from 5(6)-carboxyfluorescein-diacetate (cFDA). Protease activity was measured as the amount of BODIPY FL released from BODIPY FL casein as substrate. The strains showed a wide range of -glucosidase, esterase and protease activity. -glucosidase and esterase activity was detected in the intact cells and culture supernatant fluid of the studied strains. Only 50 % of the strains showed protease activity, which was detected only in the intact cells. The results of this study confirm the ability of O. oeni to produce extra cellular -glucosidase and esterase that could have an impact on wine flavour. The production of extra cellular protease could have an influence on the bacteria metabolism and the stability of wine. The knowledge regarding the distribution of these activities can provide another tool for the selection of O. oeni strains to use as starters to induce malolactic fermentation in wine.