CONTINUOUS FERMENTATION IN RELATION TO YEAST METABOLISM

In homogeneous systems for the continuous fermentation of wort by Saccharomyces cerevsiae fluctuations often occur in the ability of cells to remove and ferment sugars even under steady-state conditions. In partially closed systems of this type where high concentrations of yeast are accumulated and growth is suppressed, such fluctuations are magnified. The results of these fluctuations are demonstrated and the causes and results of a simultaneous decline in the rate of removal and fermentation of maltose are discussed. Such undesirable effects are largely eliminated by the use of a system which incorporates at least two stages and a continuous fermentor of such a design has operated with a high degree of stability at dilution rates as high as 0·4 h^?1.