title: Screening and evaluation of the glucoside hydrolase activity in Saccharomyces and Brettanomyces brewing yeasts.
abstract: OBJECTIVE
  The aim of this study was to select and examine Saccharomyces and Brettanomyces brewing yeasts for hydrolase activity towards glycosidically bound volatile compounds.
  
  
  RESULTS
  A screening for glucoside hydrolase activity of 58 brewing yeasts belonging to the genera Saccharomyces and Brettanomyces was performed. The studied Saccharomyces brewing yeasts did not show 1,4-beta-glucosidase activity, but a strain dependent beta-glucanase activity was observed. Some Brettanomyces species did show 1,4-beta-glucosidase activity. The highest constitutive activity was found in Brettanomyces custersii. For the most interesting strains the substrate specificity was studied and their activity was evaluated in fermentation experiments with added hop glycosides. Fermentations with Br. custersii led to the highest release of aglycones.
  
  
  CONCLUSIONS
  Pronounced exo-beta-glucanase activity in Saccharomyces brewing yeasts leads to a higher release of certain aglycones. Certain Brettanomyces brewing yeasts, however, are more interesting for hydrolysis of glycosidically bound volatiles of hops.
  
  
  CONCLUSIONS
  The release of flavour active compounds from hop glycosides opens perspectives for the bioflavouring and product diversification of beverages like beer. The release can be enhanced by using Saccharomyces strains with high exo-beta-glucanase activity. Higher activities can be found in Brettanomyces species with beta-glucosidase activity.
authors.affiliation: Department of Microbial and Molecular Systems, Centre for Malting and Brewing Science, Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, Leuven, Belgium. luk.daenen@biw.kuleuven.be
authors.forename: L
authors.initials: L
authors.lastname: Daenen
authors.forename: D
authors.initials: D
authors.lastname: Saison
authors.forename: F
authors.initials: F
authors.lastname: Sterckx
authors.forename: F R
authors.initials: FR
authors.lastname: Delvaux
authors.forename: H
authors.initials: H
authors.lastname: Verachtert
authors.forename: G
authors.initials: G
authors.lastname: Derdelinckx
mesh_terms: D001515:Beer; D005285:Fermentation; D005516:Food Microbiology; D005966:Glucuronidase / Q000032:analysis / Q000378:metabolism; D006027:Glycosides / Q000378:metabolism; D016533:Mycological Typing Techniques; D012440:Saccharomyces / Q000201:enzymology; D013649:Taste; D015003:Yeasts / Q000201:enzymology*; D001617:beta-Glucosidase / Q000032:analysis / Q000378:metabolism
chemical_list: D006027:Glycosides; D001617:beta-Glucosidase; D005966:Glucuronidase