Production and characterization of a β-glucosidase from Issatchenkia terricola and its use for hydrolysis of aromatic precursors in Cabernet Sauvignon wine

- The production of β-glucosidase from Issatchenkia terricola was optimized.
- β-Glucosidase was very active on the hydrolysis of red wine glucosides.
- GC-MS analysis of treated wine revealed the release of several volatile compounds.
- Sensory evaluation showed significant differences between treated and control wine.
- β-Glucosidase developed wine aroma without compromising its color.

New enzymes isolated from the biodiversity of native wine ecosystems could contribute to increase the varietal character of regional wines. This study reports on the production and characterization of Issatchenkia terricola, beta-glucosidase and its potential to release red-wine aromatic compounds. The enzyme, a monomer of 48 kDa with an isoelectric point of 3.5 is tolerant to glucose and ethanol, properties compatible with enological use. Although fed-batch is usually the most suitable system for enzyme production in submerged culture, in this case the yield was practically the same as in batch culture. Enzyme productivity was increased 2-fold in synthetic medium with glucose with respect to the YPG and 3-8-fold with respect to other media assayed. After enzymatic treatment, GC-MS analysis of the released aglycones demonstrated significant increases in the concentration of phenols (83%) and norisoprenoids (65%). According to the judges of the sensory panel, the treatment resulted in a wine with dried fruits and raisins notes, as compared to the control, which was found more sweet and fruity. This, together with the lack of activity on anthocyanin glycosides, highlights the potential of this enzyme in enology, since its high selectivity allowed the development of aroma without compromising wine color.