Two control algorithms were implemented in the stabilization of the dissolved oxygen concentration of the penicillin process production phase. A deterministic and nonstructured mathematical model was used, where were considered the balances of cell, substrate, dissolved oxygen and product formation as well as kinetic of the growth, respiration, product inhibition due to excess of substrate, penicillin hydrolyze, yield factors among cell growth, substrate consumption and dissolved oxygen consumption. The bioreactor was operated in a feed-batch way using an optimal strategy for the operational policy. The agitation speed was used as manipulated variable in order to achieve the dissolved oxygen control because it was found to be the most sensitive one. Two types of control configurations were implemented. First, the PID feedback control with the parameters estimated through Modified Simplex optimization method using the IAE index, and second, the DMC predictive control that had as control parameters the model, prediction and control horizons as well as suppression factor and the trajectory parameter. A sensitivity analysis of these two control algorithms was performed using the sample time and dead time as the index to make stability evaluation. Both configurations showed stable performance, however, the predictive one was found to be more robust in relation to the sample time, as well as the dead time variations. This is a very important characteristic to be considered for the implementation of control scheme in real fermentative process
DMC Control; feed-batch bioreactor; dissolved oxygen; penicillin process
