Nonlinear control of the dissolved oxygen concentration integrated with a biomass estimator for production of Bacillus thuringiensis δ-endotoxins

Abstract

Bacillus thuringiensis is a microorganism that allows the biosynthesis of -endotoxins with toxic prop-erties against some insect larvae, being often used for the production of biological insecticides. A keyissue for the bioprocess design consists in adequately tracking a pre-specified optimal profile of the dis-solved oxygen concentration. To this effect, this paper aims at developing a novel control law based on anonlinear dynamic inversion method. The closed-loop strategy includes an observer based on a BayesianRegression with Gaussian Process, which is used for on-line estimating the biomass present in the biore-actor. Unlike other approaches, the proposed controller leads to an improved response time with effectivedisturbance rejection properties, while simultaneously prevents undesired oscillations of the dissolvedoxygen concentration. Simulation results based on available experimental data were used to show theeffectiveness of the proposal.