Online estimation of kinetic rates in a baker´s yeast fed-batch bioprocess

The growth rates of the micro-organisms in bioreactors are described by complex kinetic expressions, and the modeling and estimation of such kinetics are essential for the design of control strategies. This paper deals with the on-line estimation of kinetic rates of a baker´s yeast process, taking place inside a Fed-batch Bioreactor. This bioprocess is widely used in bioindustry; its model is highly nonlinear and, furthermore, the available on-line measurements are lack and the reaction kinetics is not perfectly known. The unknown kinetics is estimated by using nonlinear observers, based on high-gain approach. Two high-gain observers are designed and implemented: one for the growth rates, and one for the reaction rates of the baker´s yeast bioprocess. The multiple estimation schemes do not require any model for the kinetic rates. Numerical simulations are included in order to test the behavior and the performance of the proposed observers.