Multiple dynamic process modes for development and characterization of bioprocesses

Abstract

Enhancing the product concentration in the harvest can greatly reduce downstream costs and consequently improve process economics. The main challenges are to increase titer, to enhance formation of intracellular target protein in soluble form and to direct target protein into the extracellular medium. This can be achieved by process design which is an easier and cheaper approach than the cell design approach. In this work, dynamic conditions were systematically implemented to overcome challenges mentioned above. Three kinds of stress were investigated: substrate-, temperature- and oxygen- related stress. The analysis showed that the production of the intracellular alkaline phosphatase in Escherichia coli was increased two folds and the oscillatory feed profile enhanced its selective release by 60%. In addition, Pichia pastoris cells produced two times more horseradish peroxidase as they experienced oxygen-limitation periodically in a two-compartment system. Hence, the two-compartment processing and an oscillatory feed profile were proposed as novel process technologies to enhance production of horseradish peroxidase in P. pastoris and recombinant alkaline phosphatase in E. coli respectively. At last, we proposed a methodology to analyze the benefits of the two-compartment processing in terms of investment cost and revenue when it would be implemented in an existing plant. The present study introduced dynamic conditions as a tool to enhance recombinant protein production. Novel process modes based on dynamic conditions were suggested. Their scalability and extrapolation to larger scaled were discussed. Hence, dynamic process modes were proposed as an attractive process mode.