Anion-exchange membrane chromatography for purification of rotavirus-like particles

Anion-exchange chromatography is one of the separation processes of choice for the recovery/purification of proteins and complex bio-structures as viruses or virus-like particles (VLPs), e.g., rotavirus-like particles (RLPs) representing a potential biopharmaceutical, where a safer vaccine technology is endeavored. Purification strategies of complex bioparticles are as yet rather empirical. The breakthrough pursued hereby was to gain theoretical and predictive knowledge on the anion-exchange membrane chromatography processing of this type of products. Currently, the use of membrane chromatography is expanding due to its scalability, robustness and disposable nature, allowing high fluxes, rapid processing, little buffer consumption and a validation-free environment. A novel matrix, Sartobind™ D membrane adsorber from Sartorius, was used and thoroughly studied for the adsorption of VLPs. Screening studies showed the sensitive effect of the ionic strength and the pH of the equilibration buffer on product final recovery. Steric mass action (SMA) model formulation was implemented for the prediction of the elution profile of purified RLP pulses. Experimental data fitting gave good model validation therefore yielding insights on the fundamental understanding of the ion-exchange separation mechanism of virus-like particles and, potentially, for other similar structures. Anion-exchange membrane chromatography was finally used in a larger scale downstream process, confirming that rotavirus VLPs can be reproductively purified to clinical grade at 46% global recovery yield, concomitant with nearly 100% removal of host bulk DNA and approximately 98% of host cell proteins.