Mathematical modelling and variable structure control systems for fed-batch fermentation of Escherichia coli

In this paper some problems of the mathematical modelling and high control algorithms of feed-batch fermentation process of Escherichia coli are considered. An unstructured mathematical model for E. coli feed-batch fermentation is developed on the base of FIA measurements. Methodology for the models' parameters estimation is proposed on the basis of nonlinear optimization methods. The model accurately predicts the process of cultivation of E. coli. On the base of the obtained model high control algorithms, such as conventional variable structure systems, variable structure systems with boundary layer and fuzzy variable structure systems, are elaborated. Glucose control strategy of feed-batch cultivation of E. coli, according to peculiarities of FIA, is presented to establish small glucose concentration to prevent the accumulation of growth inhibiting metabolites. The presented control algorithms enable to control the glucose concentration at a set point of 0.1 g l(-1).