Flocculation in Saccharomyces Cerevisiae as Influenced by Wort Composition and by Actidione

The stage during the fermentation of wort at which cells flocculate is shown to vary with the extent of exponential growth, so that the use of worts with a high content of assimilable nitrogen leads to delayed flocculation. Additionally, the presence of a high concentration of lysine, which inhibits post-exponential growth, retards flocculation still further and may prevent its occurrence. Addition of actidlone to a growing culture inhibits further increase in cell mass and prevents flocculation occurring, although the use of sugar continues; cell wall synthesis is restricted and mannan production is particularly repressed by actidione treatment.