Applied Microbiology and Biotechnology

, Volume 97, Issue 1, pp 223–235

Yeast genes involved in sulfur and nitrogen metabolism affect the production of volatile thiols from Sauvignon Blanc musts

Applied genetics and molecular biotechnology

DOI: 10.1007/s00253-012-4198-6

Cite this article as:
Harsch, M.J. & Gardner, R.C. Appl Microbiol Biotechnol (2013) 97: 223. doi:10.1007/s00253-012-4198-6
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Abstract

Two volatile thiols, 3-mercaptohexan-1-ol (3MH), and 3-mercaptohexyl-acetate (3MHA), reminiscent of grapefruit and passion fruit respectively, are critical varietal aroma compounds in Sauvignon Blanc (SB) wines. These aromatic thiols are not present in the grape juice but are synthesized and released by the yeast during alcoholic fermentation. Single deletion mutants of 67 candidate genes in a laboratory strain of Saccharomyces cerevisiae were screened using gas chromatography mass spectrometry for their thiol production after fermentation of SB grape juice. None of the deletions abolished production of the two volatile thiols. However, deletion of 17 genes caused increases or decreases in production by as much as twofold. These 17 genes, mostly related to sulfur and nitrogen metabolism in yeast, may act by altering the regulation of the pathway(s) of thiol production or altering substrate supply. Deleting subsets of these genes in a wine yeast strain gave similar results to the laboratory strain for sulfur pathway genes but showed strain differences for genes involved in nitrogen metabolism. The addition of two nitrogen sources, urea and di-ammonium phosphate, as well as two sulfur compounds, cysteine and S-ethyl-L-cysteine, increased 3MH and 3MHA concentrations in the final wines. Collectively these results suggest that sulfur and nitrogen metabolism are important in regulating the synthesis of 3MH and 3MHA during yeast fermentation of grape juice.

Keywords

Saccharomyces cerevisiaeSauvignon BlancSingle-gene deletionAroma compoundsWineVarietal thiols

Supplementary material

253_2012_4198_MOESM1_ESM.pdf (371 kb)
ESM 1(PDF 370 kb)

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.School of Biological SciencesUniversity of AucklandAucklandNew Zealand
  2. 2.Centre de Recherche Pernod RicardCréteil CedexFrance