title: Purification and characterization of an ethanol-tolerant β-glucosidase from Sporidiobolus pararoseus and its potential for hydrolysis of wine aroma precursors.
abstract: An extracellular ethanol-tolerant β-glucosidase from Sporidiobolus pararoseus was purified to homogeneity and characterized, and its potential use for the enhancement of wine aroma was investigated. The crude enzymatic extract was purified in four steps (concentration, dialysis, ultrafiltration, and chromatography) with a yield of around 40 % for total activity. The purified enzyme (designated Sp-βgl-P) showed a specific activity of approximately 20.0 U/mg, an estimated molecular mass of 63 kDa after sodium dodecyl sulfate polyacrylamide gel electrophoresis, and isoelectric point of 5.0 by isoelectric focusing. Sp-βgl-P has optimal activity at pH 4.0 and at 55 °C. It was stable in a broad pH range at low temperatures and it was tolerant to ethanol and glucose, indicating suitable properties for winemaking. The hydrolysis of glycosidic terpenes was analyzed by adding Sp-βgl-P directly to the wines. The released terpene compounds were evaluated by gas chromatography/mass spectrometry. The enzymatic treatment significantly increased the amount of free terpenes, suggesting that this enzyme could potentially be applicable in wine aroma improvement.
authors.affiliation: Agricultural Sciences Institute (ICIAG), Uberlândia Federal University (UFU), 38405-303,, Uberlândia, Minas Gerais, Brazil, millabaffi@yahoo.com.br.
authors.forename: Milla Alves
authors.initials: MA
authors.lastname: Baffi
authors.forename: Natália
authors.initials: N
authors.lastname: Martin
authors.forename: Thaise Mariá
authors.initials: TM
authors.lastname: Tobal
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: Ferrarezi
authors.forename: João Henrique Ghilardi
authors.initials: JH
authors.lastname: Lago
authors.forename: Maurício
authors.initials: M
authors.lastname: Boscolo
authors.forename: Eleni
authors.initials: E
authors.lastname: Gomes
authors.forename: Roberto
authors.initials: R
authors.lastname: Da-Silva
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D000431:Ethanol / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D009812:Odorants; D013379:Substrate Specificity; D013696:Temperature; D013729:Terpenes / Q000032:analysis / Q000737:chemistry; D014920:Wine; D001617:beta-Glucosidase / Q000096:biosynthesis / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D008670:Metals; D013729:Terpenes; D000431:Ethanol; D001617:beta-Glucosidase; D005947:Glucose