Development and Investigation of Efficient Substrate Feeding and Dissolved Oxygen Control Algorithms for Design of Recombinant E. coli Cultivation Process

摘要

The paper deals with model-based development and implementation of efficient control strategies for recombinant protein synthesis in fed-batch E. coli cultivation process. Based on experimental data, a kinetic dynamic model for the cultivation process was developed. This model was used to determine substrate feeding strategies during the cultivation. The proposed feeding strategies consist of two phases - biomass growth phase and recombinant protein production phase. In the first process phase, substrate-limited process is recommended when the biomass specific growth rate is about 90-95% of its maximum value. This ensures glucose concentration limitation in medium, improves process repeatability, reduces development of secondary metabolites and other undesired by-products. The substrate limitation can be enhanced to satisfy restriction on maximum oxygen transfer rate in the bioreactor and to guarantee necessary dissolved carbon dioxide concentration in culture media. In the recombinant protein production phase, the level of substrate limitation and specific growth rate are selected within the range to maintain optimal target protein synthesis rate. To account for complex process dynamics, efficiently exploit the oxygen transfer capability of the bioreactor, and maintain the required dissolved oxygen concentration, adaptive control techniques for dissolved oxygen control have been proposed. The developed model-based control strategies are useful in scale-up of cultivation processes and accelerate implementation of innovative biotechnological processes for industrial applications.