Screening for yeasts able to hydrolyse arbutin in the presence of glucose or ethanol

The study was carried out using 212 glucose-fermenting yeasts isolated from Calabrian and Sicilian samples of must and wine. They were screened for β-glucosidase activity in Petri plates containing arbutin agar medium. Eleven strains (three apiculate yeasts and eight elliptic yeasts) were able to perform arbutin hydrolysis, but only strain C5, identified as Pichia anomala, maintained the ability to hydrolyse arbutin even in the presence of remarkable amounts of glucose or ethanol. This strain did not show the capacity to excrete the β-glucosidase into the medium; effectively, the enzymatic activity in the culture supernatant was near to zero. However, its intracellular activity was high.