Characterization of the recombinant Brettanomyces anomalus beta-glucosidase and its potential for bioflavouring

Aim: Plant materials used in the food industry contain up to five times morearomas bound to glucose (glucosides) than free, unbound aromas, makingthese bound aromas an unused flavouring potential. The aim of this study wasto identify and purify a novel b-glucosidase from Brettanomyces yeasts that arecapable of releasing bound aromas present in various food products.Methods and Results: We screened 428 different yeast strains for b-glucosidase activity and are the first to sequence the whole genome of twoBrettanomyces yeasts (Brettanomyces anomalus and Brettanomyces bruxellensis)with exceptionally high b-glucosidase activity. Heterologous expression andpurification of the identified B. anomalus b-glucosidase showed that it has anoptimal activity at a higher pH (575) and lower temperature (37°C) thancommercial b-glucosidases. Adding this B. anomalus b-glucosidase to cherrybeers and forest fruit milks resulted in increased amounts of benzyl alcohol,eugenol, linalool and methyl salicylate compared to Aspergillus niger andAlmond glucosidase.Conclusions: The newly identified B. anomalus b-glucosidase offers newpossibilities for food bioflavouring.Significance and Impact of the Study: This study is the first to sequence theB. anomalus genome and to identify the b-glucosidase-encoding genes of twoBrettanomyces species, and reports a new bioflavouring enzyme.