Inverse Flocculation Patterns in Saccharomyces cerevisiae UOFS Y-2330
C.J. Strauss 1, J.L.F. Kock 1, 5, P.W.J. van Wyk 2, B.C. Viljoen 1, P.J. Botes 1, G. Hulse 3 and S. Nigam 4
1Department of Microbiology, Biochemistry and Food Science, University of the Free State, P.O. Box 339, Bloemfontein 9301, South Africa
2 Centrum for Confocal & Electron Microscopy, University of the Free State, P.O. Box 339, Bloemfontein 9301, South Africa
3South African Breweries, 69 Park Lane, Sandown, P.O. Box 782178, Sandton, 2146, South Africa
4 Eicosanoid Research Division, Department of Gynecology, University Medical Centre Benjamin Franklin, Free University Berlin D-12200, Berlin, Germany
5 Corresponding author: E-mail: Kockjl@sci.uovs.ac.za
J. Inst. Brew. 109(1), 3-7, 2003 | VIEW ARTICLE
ABSTRACT
An interesting yeast strain was uncovered which showed an inverse flocculation pattern when cultivated in chemically defined and complex media. When inoculated in a defined medium with glucose as a sole carbon source, this strain immediately flocculated strongly and lost this ability before stationary phase was reached. In a complex malt medium containing glucose, this yeast strongly flocculated throughout the exponential and stationary growth phases. This inverse pattern may be ascribed to a switch in sensitivity of the yeast to flocculate in the presence of glucose as well as pH level, which may, in turn, influence the availability of calcium ions. In both media, matured cells produced protuberances or "wrinkles" upon flocculation as observed by electron and immunofluorescence microscopy. These protuberances may be involved in cell adhesion during the flocculation process.
Key words:
Calcium, 3-hydroxyoxylipins, inverse flocculation, pH, Sacch. cerevisiae, sugars, zymolectin.
Publication no. G-2003-0214-081 © 2003 The Institute & Guild of Brewing