ANALYSIS OF SYNCHRONOUS GROWTH OF BAKERS-YEAST .2. COMPARISON OF MODEL PREDICTION AND EXPERIMENTAL-DATA

The population balance model for growth of baker's yeast with sustaine d synchronous oscillations is further evaluated to predict the permiss ible region of doubling times for the oscillations, the preferred regi on, and the preferred mode of oscillation. The comparison of model pre dictions and experimental data reveals that sustained oscillations can only exist in a region where the length of the parent cycle is increa sed, and the length of the daughter cycle is decreased, in reference t o asynchronous growth. While the oscillation frequency is given by the lengths of the parent and daughter cycles together with the average d oubling time, the preferred region of oscillations of a certain mode i s determined by the length of the budding phase which also controls th e oscillation amplitude and the increase in the average fraction of bu dding cells over asynchronous growth. From these two parameters, the p referred region of the oscillations is predicted and compares well to experimental data. The validity of the model is further tested by dyna mic simulations of synchronous growth. The inherent structure of the m odel allows a clear separation of cell cycle related parameters and of the age distribution of the population, by which the identification o f both from experimental data is greatly facilitated. The predicted te ndency of the oscillation amplitude in dependency on the oscillation f requency is also in good agreement with experimental data for the CO2 evolution. The theoretical analysis shows that two different types of synchronous oscillations exist under excess of oxygen and oxygen limit ation. The latter one, with oscillation periods greater than the doubl ing time, cannot be explained by the model.