Protein separation in carousel multicolumn setup. Performance analysis and experimental validation.

To overcome limitations of periodic separations of proteins in batch chromatographic columns Carousel Multi-Column Setup (CMS) has been recently suggested and theoretically analyzed in a previous study (R. Bochenek, W. Marek, W. Piątkowski, D. Antos, J. Chromatogr. A, 1301 (2013) 60-72). In this system, feed and mobile phase streams are subsequently delivered through parallel columns to mimic their countercurrent movement with respect to the fluid flow. All fluxes in the system are synchronized to ensure continuous feed delivery, which however causes reduction in the size of the operating window compared to batchwise-operating systems. In this study to improve the performance of CMS, additional process variables have been considered, such as the flow rate gradient and feed concentration. Though altering both variables allowed improving the separation selectivity and extending the operating window, the feed concentration appeared to be the most influential parameter affecting the process performance. Moreover, a procedure for practical realization of protein separations in CMS has been developed, including hints about the process design, configuration of columns and detectors, and use of pumps. As the case study, the separation of a ternary mixture of proteins, i.e., cytochrome C, lysozyme and immunoglobulin G, on hydrophobic interaction columns was used. A target product was a protein with intermediate adsorption strength that was isolated out of a more and less strongly adsorbed compound.