Mitochondrial Associated Yeast Flocculation – The Effect of Acetylsalicylic Acid
C.J. Strauss1, P.W.J. van Wyk2, E.J. Lodolo3, P.J. Botes1, C.H. Pohl1, S. Nigam4 and J.L.F. Kock1,5
1 UNESCO MIRCEN: Industrial Biotechnology, Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, P.O. Box 339, Bloemfontein, South Africa.
2 Center for Confocal and Electron Microscopy, University of the
Free State, P.O. Box 339, Bloemfontein, South Africa.
3 SABMiller plc, 65 Park Lane, P.O. Box 782178, Sandton, 2146, South Africa.
4 Eicosanoid and Lipid Research Division, and Centre for Experimental Gynecology and Breast Research, University Medical Center Benjamin Franklin, Free University Berlin D-12200, Berlin, Germany.
5 Corresponding author. E-mail: kockjl.sci@mail.uovs.ac.za
J. Inst. Brew. 113(1), 42–47, 2007 | VIEW ARTICLE
ABSTRACT
Mitochondrial function is generally accepted as important for expression of yeast flocculation. In this study, a correlation between mitochondrial activity and flocculation is demonstrated using the XTT reduction assay. The mitochondrial activity of strongly flocculent cells was higher than those of weakly flocculent cells and cells cultivated in the presence of acetylsalicylic acid. Furthermore, we show the first oxylipin-containing flocculation binding sites on yeast cell surfaces using scanning electron microscopy. We propose that in addition to zymolectinmediated flocculation, oxylipin interactions may also play a role in yeast flocculation.
Key words:
3-Hydroxy oxylipins, binding sites, electron microscopy, flocculation, mitochondria, Saccharomyces cerevisiae, XTT reduction assay.
Publication no. G-2007-0416-507 ©2007 The Institute & Guild of Brewing