Optimization of culture conditions for the production of β-glucosidase from an uruguayan strain of Issatchenkia terricola and study of aroma release in C. Sauvignon wine.

DE OVALLE, STEFANI; CAVELLO, I.; BRENA, BEATRIZ M.; CAVALITTO, S; GONZÁLEZ-POMBO, PAULA

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Congreso; International Congress on Grapewine and Wine Sciences; 2018

Instituto de Ciencias de la Vid y el Vino

A major fraction ofaromatic compounds are linked to sugars, as non-volatile compounds,representing a significant reservoir of aroma to be released (González-Pombo etal., 2014). β-D-glucosidase is a key enzyme in the enzymatic hydrolysis ofthese aroma precursors and thus, an useful tool to be use in the development ofaroma. β-glucosidase from Issatchenkia terricola is a monomer of 48 kDawith an isoelectric point of 3.5. It is tolerant to glucose and ethanol,properties compatible with enological use. It has been demonstrated to beactive against several aroma precursors of muscat wine, showing more specificitytowards norisoprenoids (González-Pombo et al., 2011). As these compounds areassociated to honey, nuts and raisins notes, it is interesting to study thisenzyme in a red wine. A limitation in it use is the usual low productivity whenwild strains are used. In this work, culture conditions were modified in orderto improve enzyme production as well as the aroma profile of Cabernet Sauvignonwas studied after wine enzymatic treatment. Enzyme productivity was increased2-fold in a synthetic medium with glucose as carbon source with respect to theYPG (control medium) and 3 to 8-fold with respect to other media assayed. Enzymeproduction increased concomitantly with O.D., showing that it is associatedwith yeast growth. The maximum production of enzyme was observed at 28º C andpH 5-6. The scaling up was assayed in both, batch and fed-batch culture. Althoughthe latter is usually the most suitable system for enzyme production insubmerged culture, in this case the yield was practically the same as in batch culture. GC-MS analysis of aglycones after enzymatichydrolysis revealed significant increases in the concentrationof phenols (83%) and norisoprenoids (65%) resulting in a wine with dried fruitsand raisins notes (de Ovalle et al., 2018)