Model-based optimization of viral capsid protein production in fed-batch culture of recombinant Escherichia coli

Abstract

An optimized fed-batch cultivation process for the production of the polyoma virus capsid protein VP1 in recombinant Escherichia coli BL21 bacteria is presented. The optimization procedure maximizing the amount of desired protein is based on a mathematical model. The model distinguishes an initial cell growth phase from a protein production phase initiated by inducer injection. A new approach to model the target protein formation rate was elaborated, where product formation is primarily dependent on the specific biomass growth rate. Lower growth rates led to higher specific protein concentrations. The model was identified from a series of fed-batch experiments designed for parameter identification purposes and possesses good prediction quality. Then the model was used to determine optimal open-loop control profiles by manipulating the substrate feed rates in both phases as well as the induction time. Feed-rate optimization has been solved using Pontryagin's maximum principle. The solution was validated experimentally. A significant improvement of the process performance index was achieved.

Recombinant protein production in an Escherichia coli reduced genome strain

“…At the lower fed-batch growth rate, the specific CAT activity remained elevated for a longer time period. Both of these expression characteristics are similar to what has been observed for E. coli MG1655 under similar conditions (Hoffman et al, 2002;Koo and Park, 1999;Levisauskas et al, 2003;Riesenberg et al, 1990).…”

“…Thus, it is possible that the lower observed specific CAT activity in the high fed-batch growth rate fermentation cultures could have been due to redirection of the carbon resources from the recombinant protein to acetate, due to overflow metabolism, as seen with E. coli MG1655. The effect of growth rate on recombinant protein expression has been addressed in literature for strains related to E. coli MG1655, and the E. coli MDS40 strain behavior was consistent with respect to productivity and growth rates (Hoffman et al, 2002;Koo and Park, 1999;Levisauskas et al, 2003;Riesenberg et al, 1990). …”

Application of Genetic Algorithms and Ant Colony Optimization for Modelling of E. coli Cultivation Process

“…The following upper and lower bounds are considered (Cockshott & Bogle, 1999;Levisauskas et al, 2003):…”

Application of a Fed-Batch Bioprocess for the Heterologous Production of hSCOMT in Escherichia coli

“…Recently, there has been increasing awareness in the use of model predictive approaches for protein expression systems [10,18]. Predictive control approaches are easy to understand and provide a straightforward way to explicitly handle constraints [14].…”