초록
Screening for optimal refolding conditions for recombinant protein overexpressed in Escherichia coli as inclusion bodies is often carried out on micro-scale in non-agitated reactors. Currently, scale up of refolding of N<SUP>pro</SUP> fusion proteins is based on geometric similarity and constant Re number. Refolding/cleavage kinetics is recorded offline by HPLC and via fluorescence intensity. We show that the results for refolding obtained on the micro-scale can be transferred to the laboratory scale stirred tank reactor, with increases in scale up to a factor of 5000, with high agreement of kinetic constants and yield. Progress of refolding kinetics on the laboratory scale is monitored inline by attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR). Addressing the demands for better process understanding, we demonstrate that ATR-FTIR enables the inline monitoring of refolding processes on the laboratory scale, replacing offline analysis which delivers the results with a time delay. Implementing inline monitoring will allow the integration of process control, thereby resulting in a more efficient and knowledge based production process.