A simple structured model for continuous production of a hybrid antibioticby Streptomyces lividans pellets in a fluidized-bed bioreactor

A simple structured model is developed for the description of the experimen ts of continuous production of a hybrid antibiotic by Streptomyces lividans TK21 pellets in a fluidized-bed reactor. The model is based on the effect of internal and external phosphate concentrations on antibiotic production during cyclic feeding. These concentrations can be calculated on the basis of the equations postulated by the model. The model also considers the cell growth, reflected in changes of the pellet size along the culture. The mod el parameters are evaluated sequentially by performing experiments at diffe rent operational conditions. The validity of the model and its correspondin g parameters is corroborated further by the satisfactory modeling of the bi oreactor operation during an extended period of time at various operation c onditions.