Monitoring of Brewing Yeast Propagation Under Aerobic and Anaerobic Conditions Employing Flow Cytometry
J. Novak1, G. Basarova1, J. A. Teixeira2,3 and A. A. Vicente2
1 Institute of Chemical Technology Prague, Department of Fermentation Chemistry and Bioengineering, Czech Republic.
2 IBB – Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
3 Corresponding author. E-mail: jateixeira@deb.uminho.pt
J. Inst. Brew. 113(3), 249–255, 2007 | VIEW ARTICLE
ABSTRACT
The vitality and viability of industrial strains ofSaccharomyces Cerevisiae was monitored during pilot plant experiments simulating yeast propagation under aerobic and anaerobic conditions. Industrial wort of 12°P original gravity was used as a growth substrate for yeast propagation. The work was carried out with three widely used Czech lager yeast industrial strains: strains 2, 7 and 95. Cell cycle, cell size, granularity, glycogen content, DNA and protein content were analyzed by flow cytometry. Significantly higher specific growth rates, higher content of yeast glycogen, earlier G2/M phase cells maximum, and faster cell protein creation was observed under aerobic conditions compared to anaerobic. Strains 7 and 95 showed losses in flocculation ability after aerobic propagation compared to anaerobic propagation. Under either aerobic or strictly anaerobic conditions, only strain 2 did not show a significant loss in flocculation ability.
Key words:
Cell cycle, fluorescent methods, proteins, yeast glycogen, yeast propagation.
Publication no. G-2007-1121-471 ©2007 The Institute & Guild of Brewing