Quantification of Glycosidase Activity in Selected Strains ofBrettanomyces bruxellensisandOenococcus oeni

Brettanomyces bruxellensis and lactic acid bacteria are common microorganisms capable of modifying wine aroma and flavor. The activity of β-glucosidase against p-nitrophenyl-β-D-glucopyranoside was determined in a model system for 14 strains of Brettanomyces bruxellensis yeast and 9 strains of lactic acid bacteria (Oenococcus oeni). All Brettanomyces strains and 7 Oenococcus strains exhibited enzymatic activity against this substrate. B. bruxellensis β-glucosidase activity was primarily intracellular; O. oeni showed some extracellular activity. Strains showing activity greater than 1000 nmole mL-1 g dry cell mass-1 24 hr-1 for Brettanomyces, or 100 nmole mL-1 g dry cell mass-1 24 hr-1 for Oenococcus, were evaluated for their effect on native Viognier grape glycosides. Neither genus was active on Viognier grape glycosides.