PURIFICATION AND CHARACTERIZATION OF THE ENDOCELLULAR BETA-GLUCOSIDASE OF A NEW STRAIN OF CANDIDA-ENTOMOPHILA ISOLATED FROM FERMENTING AGAVE (AGAVE SP) JUICE

A yeast strain isolated in the laboratory from fermenting agave (Agave sp.) juice was studied and classified as Candida entomophila. The bet a-glucosidase of this yeast was purified by ion-exchange chromatograph y and gel filtration. Its molecular mass estimated by gel filtration w as 400 kDa. The oligomeric structure was determined following treatmen t of the purified enzyme with SDS. Its optimum pH was between 5 and 6, and its optimum temperature was 60 degrees C. The enzyme was active a gainst soluble glucosides with (1 --> 3)-beta, (1 --> 4)-beta and (1 - -> 4)-alpha linkage configuration, and it possesses (1 --> 6)-alpha-ar abinofuranosidase activity. It is competitively inhibited by glucose a nd by D-gluconic acid lactone. The enzyme was constitutive and a gluco syltransferase activity is observed in the presence of ethanol. Since the glycosides present in wines and fruit juices represent a potential source of aromatic flavour, the possible use of the yeast glucosidase for the liberation of the bound aroma is discussed.