title: Identification of target genes to control acetate yield during aerobic fermentation with Saccharomyces cerevisiae.
abstract: BACKGROUND
  Aerobic fermentation of grape must, leading to respiro-fermentative metabolism of sugars, has been proposed as way of reducing alcohol content in wines. Two factors limit the usefulness of Saccharomyces cerevisiae for this application, the Crabtree effect, and excess volatile acidity under aerobic conditions. This work aimed to explore the impact on ethanol acetate production of different S. cerevisiae strains deleted for genes previously related with the Crabtree phenotype.
  
  
  RESULTS
  Recombinant strains were constructed on a wine industrial genetic background, FX10. All yeast strains, including FX10, showed respiro-fermentative metabolism in natural grape must under aerobic conditions, as well as a concomitant reduction in ethanol yield. This indicates that the Crabtree effect is not a major constrain for reaching relevant respiration levels in grape must. Indeed, only minor differences in ethanol yield were observed between the original and some of the recombinant strains. In contrast, some yeast strains showed a relevant reduction of acetic acid production. This was identified as a positive feature for the feasibility of alcohol level reduction by respiration. Reduced acetic acid production was confirmed by a thorough analysis of these and some additional deletion strains (involving genes HXK2, PYK1, REG1, PDE2 and PDC1). Some recombinant yeasts showed altered production of glycerol and pyruvate derived metabolites.
  
  
  CONCLUSIONS
  REG1 and PDC1 deletion strains showed a strong reduction of acetic acid yield in aerobic fermentations. Since REG1 defective strains may be obtained by non-GMO approaches, these gene modifications show good promise to help reducing ethanol content in wines.
authors.affiliation: Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, Departamento de Enología, Instituto de Ciencias de la Vid y del Vino, Finca La Grajera, Ctra. De Burgos Km. 6, 26007, Logroño, La Rioja, Spain.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Curiel
authors.affiliation: Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, Departamento de Enología, Instituto de Ciencias de la Vid y del Vino, Finca La Grajera, Ctra. De Burgos Km. 6, 26007, Logroño, La Rioja, Spain.
authors.forename: Zoel
authors.initials: Z
authors.lastname: Salvadó
authors.affiliation: Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, Departamento de Enología, Instituto de Ciencias de la Vid y del Vino, Finca La Grajera, Ctra. De Burgos Km. 6, 26007, Logroño, La Rioja, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Tronchoni
authors.affiliation: Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, Departamento de Enología, Instituto de Ciencias de la Vid y del Vino, Finca La Grajera, Ctra. De Burgos Km. 6, 26007, Logroño, La Rioja, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Morales
authors.affiliation: Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, Departamento de Enología, Instituto de Ciencias de la Vid y del Vino, Finca La Grajera, Ctra. De Burgos Km. 6, 26007, Logroño, La Rioja, Spain.
authors.forename: Alda Joao
authors.initials: AJ
authors.lastname: Rodrigues
authors.affiliation: Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, Departamento de Enología, Instituto de Ciencias de la Vid y del Vino, Finca La Grajera, Ctra. De Burgos Km. 6, 26007, Logroño, La Rioja, Spain.|Evolva Biotech A/S, Copenhagen Ø, Denmark.
authors.forename: Manuel
authors.initials: M
authors.lastname: Quirós
authors.affiliation: Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, Departamento de Enología, Instituto de Ciencias de la Vid y del Vino, Finca La Grajera, Ctra. De Burgos Km. 6, 26007, Logroño, La Rioja, Spain. rgonzalez@icvv.es.
authors.forename: Ramón
authors.identifier: http://orcid.org/0000-0001-7388-1660
authors.initials: R
authors.lastname: Gonzalez
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000332:Aerobiosis; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D005990:Glycerol / Q000378:metabolism; D006593:Hexokinase / Q000235:genetics* / Q000378:metabolism; D054645:Protein Phosphatase 1 / Q000235:genetics* / Q000378:metabolism; D011767:Pyruvate Decarboxylase / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D027843:Vitis / Q000378:metabolism; D014920:Wine / Q000032:analysis
chemical_list: D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; C490214:HXK2 protein, S cerevisiae; D006593:Hexokinase; D054645:Protein Phosphatase 1; C070829:REG1 protein, S cerevisiae; C101504:PDC1 protein, S cerevisiae; D011767:Pyruvate Decarboxylase; D005990:Glycerol; D019342:Acetic Acid
keywords: Aerobic fermentation; Alcohol level reduction; Carbon catabolite derepression; Crabtree effect; Volatile acidity; Wine