title: De novo production of six key grape aroma monoterpenes by a geraniol synthase-engineered S. cerevisiae wine strain.
abstract: BACKGROUND
  Monoterpenes are important contributors to grape and wine aroma. Moreover, certain monoterpenes have been shown to display health benefits with antimicrobial, anti-inflammatory, anticancer or hypotensive properties amongst others. The aim of this study was to construct self-aromatizing wine yeasts to overproduce de novo these plant metabolites in wines.
  
  
  RESULTS
  Expression of the Ocimum basilicum (sweet basil) geraniol synthase (GES) gene in a Saccharomyces cerevisiae wine strain substantially changed the terpene profile of wine produced from a non-aromatic grape variety. Under microvinification conditions, and without compromising other fermentative traits, the recombinant yeast excreted geraniol de novo at an amount (~750 μg/L) well exceeding (>10-fold) its threshold for olfactory perception and also exceeding the quantities present in wines obtained from highly aromatic Muscat grapes. Interestingly, geraniol was further metabolized by yeast enzymes to additional monoterpenes and esters: citronellol, linalool, nerol, citronellyl acetate and geranyl acetate, resulting in a total monoterpene concentration (~1,558 μg/L) 230-fold greater than that of the control. We also found that monoterpene profiles of wines derived from mixed fermentations were found to be determined by the composition of the initial yeast inocula suggesting the feasibility of producing 'à la carte' wines having predetermined monoterpene contents.
  
  
  CONCLUSIONS
  Geraniol synthase-engineered yeasts demonstrate potential in the development of monoterpene enhanced wines.
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain. epardo@iata.csic.es.
authors.forename: Ester
authors.initials: E
authors.lastname: Pardo
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain. jrico@iata.csic.es.
authors.forename: Juan
authors.initials: J
authors.lastname: Rico
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain. giljv@uv.es.|Departamento de Medicina Preventiva y Salud Pública, Ciencias de la Alimentación, Bromatología, Toxicología y Medicina Legal, Facultad de Farmacia, Universidad de Valencia, Vicente Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain. giljv@uv.es.
authors.forename: José Vicente
authors.initials: JV
authors.lastname: Gil
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain. morejas@iata.csic.es.
authors.forename: Margarita
authors.initials: M
authors.lastname: Orejas
mesh_terms: D005285:Fermentation; D060847:Metabolic Engineering; D039821:Monoterpenes / Q000378:metabolism*; D018649:Ocimum basilicum / Q000201:enzymology; D009812:Odorants; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D027843:Vitis / Q000737:chemistry*; D014920:Wine
chemical_list: D039821:Monoterpenes; D010940:Plant Proteins; D011994:Recombinant Proteins; D010744:Phosphoric Monoester Hydrolases