On-line State Observers for Baker’s Yeast Fermentation

Product quality and productivity improvement of a fermentation process implies, usually, reliable online measurements. Due to the difficulties, high costs and inefficient technology to obtain on-line measurements, several methodologies were developed to overcome these problems. In this work, algorithms for on-line state observation and kinetics parameters estimation applied to fed-batch baker’s yeast fermentation process are presented. The algorithms, initially proposed by [12] are used for a brief theoretical study and validated with experimental data. Only two on-line state variables measurements, oxygen and carbon dioxide, are used to estimate all the state and the kinetics parameters. The method shows to be very sensitive to measurements precision, in particular, in the oxygen transfer rate evaluation. A corrective parameter is then introduced and consequently a better performance of the estimators is obtained.