B.A. PRIOR*,**, C. BACCARI*** and R.K. MORTIMER***
1Department of Microbiology and Biochemistry, University of the Orange Free State, Bloemfontein, South Africa 9300
2Department of Microbiology, University of Stellenbosch, Stellenbosch, South Africa 7600
3Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
Abstract : Glycerol in wines is at levels of 1 to 10 g/l and improves their body. To breed wine yeast for increased glycerol production, we crossed yeast isolated from natural fermentations with a commercial strain. The average glycerol concentration of 187 wine yeast strains was 4.2 g/l. Strain Ba25 had the highest glycerol production and a spore clone of Ba25 was crossed with one of Premier Cuvée, the best commercial strain, by spore-spore pairing and this was repeated three times. Several of the spore clones produced >15 g/l of glycerol. Glycerol and ethanol levels were inversely related.
Key words : glycerol, ethanol, wine yeast, breeding