Emergence of Ideal Membrane Cascades for Downstream Processing

Abstract

An algorithm is developed for describing ideal membrane cascades for fractionation of binary and pseudo-binary mixtures. It is shown that solvent management plays a key role in determining both purification and yield. Development of efficient diafilters is needed if membrane cascades are to achieve their full potential in competing with both chromatography and simulated moving bed operations in downstream processing of proteins. Such a replacement will also be important for fractionation of higher titers and larger substrates, such as plasmids, viruses, and even whole cells.

Continuous fractionation of plasma proteins HSA and HIgG using cascade ultrafiltration systems

“…Liquid chromatography and its variants are widely used for antibody purification since they provide high-resolution separation [4][5][6][7][8][9]. However, chromatographic purification methods are associated with certain major limitations [4][5][6]10]. The reliance on solute diffusion between stationary and mobile phases makes separation exceedingly slow, particularly for large macromolecules such as antibodies [7,8,10].…”

“…However, chromatographic purification methods are associated with certain major limitations [4][5][6]10]. The reliance on solute diffusion between stationary and mobile phases makes separation exceedingly slow, particularly for large macromolecules such as antibodies [7,8,10]. Chromatography also requires large amounts of different buffers for equilibration, elution and bed regeneration and this contributes significantly to processing cost [5].…”

“…Moreover, techniques used for antibody purification such as Protein-A or -G affinity chromatography expose the protein molecules to harsh acidic conditions, often detrimental for their stability and causing aggregation [9]. Membrane based techniques such as ultrafiltration and membrane chromatography which address some of these drawbacks seem to be attractive alternatives to column chromatography [5,[10][11][12][13][14].…”

“…Ultrafiltration processes are widely used in the bio-industry for batch concentration and diafiltration due to their scalability, high throughput and low operating cost [4,[10][11][12][13][14]. Ultrafiltration offers mild operating conditions and proteins do not have to undergo any form of phase change.…”

“…The effect of protein-protein interactions on sieving behavior was speculated but not examined in detail in this work. A careful design of membrane cascade with effective solvent management provided enhanced purification [10,20], but the effect of composition dependent sieving coefficients need to be studied for actual understanding of cascade behavior. This paper discusses the fractionation of plasma proteins HSA and HIgG using cascade ultrafiltration systems based on stirred cell ultrafiltration modules.…”