Project Number
IWBT 01-05
Project title
The cloning and characterisation of genes involved in flocculation and cell aggregation in sparkling wines and sherry
Project leader
Bauer, F F
Institution
University of Stellenbosch. Faculty of AgriSciences. Institute for Wine Biotechnology
Team members
Gupthar, A
Govender, P
Domingo, J L
Project description
– To construct a wine yeast that is able to flocculate at the end of fermentation, which can be used in the production of natural wine and bottle fermented sparkling wine for the enhancement of settling at the end of fermentation.
– To clone (a) gene(s) necessary for velum formation and use the gene(s) to optimise velum formation.
Optimally, wine yeast should meet two partially conflicting demands during wine production: during fermentation a high suspended yeast count is desirable to maintain a satisfactory rate of fermentation, while at completion, efficient settling is required to minimise problems with wine clarification. The settling of the yeast does occur efficiently when flocculating yeast strains are used. The cells of these strains are able to aggregate with each other, which leads to rapid sedimentation. Flocculating yeast strains are also of pivotal importance in the production of bottle-fermented sparkling wines. However, most wine yeasts flocculate inefficiently or not at all. Cell aggregation also plays a key role in the production of flor sherry, where a related cellular process results in velum formation. Characterisation of genes involved in flocculation and cell aggregation will shed more light on these phenomena. This could lead to the construction of yeast strains with precisely controlled flocculation and velum formation during the production of natural wine, sparkling wine and flor sherry.
Presentation(s)
Bauer, F F, Domingo, J L, Govender, P, Gupthar, A S and Pretorius I S. 2000. Development of wine yeast strains with improved flocculation properties. Paper presented at the 2nd International Congress of the South African Society for Enology and Viticulture. 8-10 November, Cape Town, South Africa.
Verstrepen, K, Bauer, F F, Michiels, C, Derdelinckx, G, Delvaux, F and Pretorius, I S. 2000. Controlled expression of FLO1 in Saccharomyces cerevisiae. Paper presented at the European Brewery Convention.
Bauer, F F, Domingo, J L, Govender, P and Pretorius, I S. 2001. The development of wine yeast strains with new flocculation properties. Paper presented at the 25th National Congress of the South African Society for Enology and Viticulture, 15-16 November, Cape Town, South Africa.
Bauer, F F, Domingo, J L, Govender, P, Gupthar, A S and Pretorius I S. 2002. Adjusting the flocculation of yeast strains to facilitate the processing of wine. Paper presented at the 22nd International Specialised Symposium on Yeast. 23-25 March, Pilanesberg, South Africa.
Article
Verstrepen, K, Derdelinckx, G, Delvaux, F, Winderickx, J, Thevelien, J M, Bauer, F F, Pretorius, I S. 2001. Late fermentation of expression of FLO1 in Saccharomyces cerevisiae, Journal of the American Society of Brewing Chemists, v. 59 (2) (p. 69-76)
Paper
Verstrepen, K, Bauer, F F, Michiels, C, Derdelinckx, G, Delvaux, F, Pretorius, I S. 1999. Controlled expression of FLO1 in Saccharomyces cerevisiae, IN: Proceedings of the 27th European Brewery Convention. 1999, Cannes, France. v. 28 (p. 30-42)