Parameter estimation of a dynamic model of Escherichia coli fed-batch cultures

Abstract

This work proposes an original sequential parameter identification method of a dynamic model of Escherichia coli BL21(DE3) fed-batch cultures. The proposed macroscopic model is based on the overflow (or bottleneck) metabolism assumption of Sonnleitner and Kappeli, suggesting two metabolic pathways (respirative and respiro-fermentative), and consists of a set of nonlinear mass balance differential equations. Model unknown parameters are estimated from dedicated experimental data collected from a 5-liter pilot bioreactor. Experiments are designed in order to force switches from one metabolic pathway to another. A sequential identification procedure, based on a specific data partitioning, is achieved and results are qualitatively and quantitatively assessed using Fisher information. The resulting dynamic model is in good agreement with the experimental data, and could be used for process optimization and/or control. The identification procedure could also easily be transposed to other processes.