title: Engineering Saccharomyces cerevisiae to release 3-Mercaptohexan-1-ol during fermentation through overexpression of an S. cerevisiae Gene, STR3, for improvement of wine aroma.
abstract: Sulfur-containing aroma compounds are key contributors to the flavor of a diverse range of foods and beverages. The tropical fruit characters of Vitis vinifera L. cv. Sauvignon blanc wines are attributed to the presence of the aromatic thiols 3-mercaptohexan-1-ol (3MH), 3-mercaptohexan-1-ol-acetate, and 4-mercapto-4-methylpentan-2-one (4MMP). These volatile thiols are found in small amounts in grape juice and are formed from nonvolatile cysteinylated precursors during fermentation. In this study, we overexpressed a Saccharomyces cerevisiae gene, STR3, which led to an increase in 3MH release during fermentation of a V. vinifera L. cv. Sauvignon blanc juice. Characterization of the enzymatic properties of Str3p confirmed it to be a pyridoxal-5'-phosphate-dependent cystathionine β-lyase, and we demonstrated that this enzyme was able to cleave the cysteinylated precursors of 3MH and 4MMP to release the free thiols. These data provide direct evidence for a yeast enzyme able to release aromatic thiols in vitro that can be applied in the development of self-cloned yeast to enhance wine flavor.
authors.affiliation: The Australian Wine Research Institute, Wine Innovation Cluster, P.O. Box 197, Urrbrae, SA 5064, Australia.
authors.forename: Sylvester
authors.initials: S
authors.lastname: Holt
authors.forename: Antonio G
authors.initials: AG
authors.lastname: Cordente
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Williams
authors.forename: Dimitra L
authors.initials: DL
authors.lastname: Capone
authors.forename: Wanphen
authors.initials: W
authors.lastname: Jitjaroen
authors.forename: Ian R
authors.initials: IR
authors.lastname: Menz
authors.forename: Chris
authors.initials: C
authors.lastname: Curtin
authors.forename: Peter A
authors.initials: PA
authors.lastname: Anderson
mesh_terms: D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005285:Fermentation; D015870:Gene Expression; D008190:Lyases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D027843:Vitis / Q000382:microbiology; D014920:Wine / Q000032:analysis*
chemical_list: C443379:3-mercaptohexan-1-ol; D004271:DNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D013438:Sulfhydryl Compounds; D008190:Lyases; C019965:cystathionine beta-lyase