title: Screening for the production of extracellular hydrolytic enzymes by non-Saccharomyces wine yeasts.
abstract: OBJECTIVE
  The objective of this study was to investigate what types of enzymes are being produced by non-Saccharomyces yeasts isolated from grapes in South Africa vineyards and clarified grape juice. These enzyme profiles could pave the way for attributing specific effects in wine to some of these enzymes produced by so-called wild yeasts associated with grape must.
  
  
  RESULTS
  In this study 245 yeast isolates, belonging to the genera Kloeckera, Candida, Debaryomyces, Rhodotorula, Pichia, Zygosaccharomyces, Hanseniaspora and Kluyveromyces were screened for the production of extracellular pectinases, proteases beta-glucanases, lichenases, beta-glucosidases, cellulases, xylanases, amylases and sulphite reductase activity. These yeasts, representing 21 species, were previously isolated from grapes and clarified grape juice. The production of all extracellular hydrolytic enzymes screened for was observed except beta-glucosidase activity. The amount and range of enzymes produced varied with different isolates of the same species.
  
  
  CONCLUSIONS
  This study clearly revealed the potential of non-Saccharomyces wine yeasts to produce a wide range of useful extracellular enzymes during the initial phase of wine fermentation.
  
  
  CONCLUSIONS
  Enzymes produced by indigenous yeasts associated with grapes and juice might be harnessed to catalyse desired biotransformations during wine fermentation.
authors.affiliation: Institute for Wine Biotechnology and Department of Viticulture and Oenology, University of Stellenbosch, 7602 Matieland (Stellenbosch), South Africa.
authors.forename: M L
authors.initials: ML
authors.lastname: Strauss
authors.forename: N P
authors.initials: NP
authors.lastname: Jolly
authors.forename: M G
authors.initials: MG
authors.lastname: Lambrechts
authors.forename: P
authors.initials: P
authors.lastname: van Rensburg
mesh_terms: D002175:Candida / Q000201:enzymology / Q000302:isolation & purification; D002480:Cellulase / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000378:metabolism; D010843:Pichia / Q000201:enzymology / Q000302:isolation & purification; D011096:Polygalacturonase / Q000378:metabolism; D012248:Rhodotorula / Q000201:enzymology / Q000302:isolation & purification; D019685:Rosales / Q000382:microbiology*; D014920:Wine; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000378:metabolism; D020068:Zygosaccharomyces / Q000201:enzymology / Q000302:isolation & purification; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D004798:Enzymes; D050862:Oxidoreductases Acting on Sulfur Group Donors; D006026:Glycoside Hydrolases; D014995:Xylosidases; D011096:Polygalacturonase; D001617:beta-Glucosidase; D043325:Xylan Endo-1,3-beta-Xylosidase; D002480:Cellulase; C028020:licheninase; D010450:Endopeptidases