A Novel Extracellular ß-Glucosidase from Trichosporon asahii: Yield Prediction, Evaluation and Application for Aroma Enhancement of Cabernet Sauvignon

The production and application of novel beta-glucosidase from Trichosporon asahii were studied. The beta-glucosidase yield was improved by response surface methodology, and the optimal media constituents were determined to be dextrin 4.67% (w/v), yeast extract 2.99% (w/v), MgSO4 0.01% (w/v), and K2HPO4 0.02% (w/v). As a result, beta-glucosidase production was enhanced from 123.72 to 215.66 U/L. The effects of different enological factors on the activity of beta-glucosidases from T. asahii were investigated in comparison to commercial enzymes. beta-Glucosidase from T. asahii was activated in the presence of sugars in the range from 10% to 40% (w/v), with the exception of glucose (slight inhibition), and retained higher relative activities than commercial enzymes under the same conditions. In addition, ethanol, in concentrations between 5% and 20% (v/v), also increased the beta-glucosidase activity. Although the beta-glucosidase activity decreased with decreasing pH, the residual activity of T. asahii was still above 50% at the average wine pH (pH 3.5). Due to these properties, extracellular beta-glucosidase from T. asahii exhibited a better ability than commercial enzymes in hydrolyzing aromatic precursors that remained in young finished wine. The excellent performs of this beta-glucosidase in wine aroma enhancement and sensory evaluation indicated that the beta-glucosidase has a potential application to individuate suitable preparations that can complement and optimize grape or wine quality during the winemaking process or in the final wine. Practical Application: The present study demonstrated the usefulness of response surface methodology based on the central composite design for yield enhancement of beta-glucosidase from T. asahii. The investigation of the primary characteristics of the enzyme and its application in young red wine suggested that the beta-glucosidase from T. asahii can provide more impetus for aroma improvement in the future.