Applied Microbiology and Biotechnology

, Volume 91, Issue 3, pp 713–730

Identifying genes that impact on aroma profiles produced by Saccharomyces cerevisiae and the production of higher alcohols

Applied Genetics and Molecular Biotechnology

DOI: 10.1007/s00253-011-3237-z

Cite this article as:
Styger, G., Jacobson, D. & Bauer, F.F. Appl Microbiol Biotechnol (2011) 91: 713. doi:10.1007/s00253-011-3237-z

Abstract

During alcoholic fermentation, many volatile aroma compounds are formed by Saccharomyces cerevisiae, including esters, fatty acids, and higher alcohols. While the metabolic network that leads to the formation of these compounds is reasonably well mapped, surprisingly little is known about specific enzymes involved in specific reactions, the regulation of the network, and the physiological roles of individual pathways within the network. Furthermore, different yeast strains tend to produce significantly different aroma profiles. These differences are of tremendous biotechnological interest, since producers of alcoholic beverages such as wine and beer are searching for means to diversify and improve their product range. Various factors such as the redox, energy, and nutritional balance of a cell have previously been suggested to directly or indirectly affect and regulate the network. To gain a better understanding of the regulations and physiological role of this network, we screened a subset of the EUROSCARF strain deletion library for genes that, when deleted, would impact most significantly on the aroma profile produced under fermentative conditions. The 10 genes whose deletion impacted most significantly on higher alcohol production were selected and further characterized to assess their mode of action within or on this metabolic network. This is the first description of a large-scale screening approach using aroma production as the primary selection criteria, and the data suggest that many of the identified genes indeed play central and direct roles within the aroma production network of S. cerevisiae.

Keywords

Ehrlich pathwayBranched chain amino acid metabolismHigher alcoholsWine aroma

Supplementary material

253_2011_3237_Fig9_ESM.jpg (2 kb)
Fig. A1

Fermentation kinetics of the deletion strains. Strains were inoculated and cultivated as stated in the “Materials and methods” section, and samples were taken every 6 h for the first 24 h and thereafter less regularly. Fifty microliters of the medium was added to 200 μl H2O in a 96-well plate, mixed by pipetting, and read at 600 nm in a Powerwave X spectrophotometer (Bio-Tek Instruments, Inc.). a Growth throughout fermentation. The data indicate that there are no statistical differences in the fermentation rate and biomass production between the various deletion strains and the wild type. b Growth during the first 48 h. No significant differences between the strains were observed during the crucial first 48-h growth period. The data suggest that the effects of the deletions on the production of higher alcohols and related compounds are due to the specific gene deletion in the strain and not the consequence of some indirect effects of the mutations on growth or fermentation performance (JPEG 2 kb)

253_2011_3237_MOESM1_ESM.tif (3.7 mb)
High resolution image (TIFF 3784 kb)
253_2011_3237_MOESM2_ESM.txt (18 kb)
Table A1Results of t test of all strains that were screened initially (TXT 17 kb)
253_2011_3237_MOESM3_ESM.doc (26 kb)
ESM 1(DOC 26 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Gustav Styger
    • 1
  • Dan Jacobson
    • 1
  • Florian F. Bauer
    • 1
  1. 1.Institute for Wine BiotechnologyStellenbosch UniversityStellenboschSouth Africa