The behavior of suspensions and macromolecular solutions in crossflow microfiltration

Hundreds of therapeutic monoclonal antibodies (mAbs) are currently in development, and many companies have multiple antibodies in their pipelines. Current methodology used in recovery processes for these molecules are reviewed here. Basic unit operations such as harvest, Protein A affinity chromatography, and additional polishing steps are surveyed. Alternative processes such as flocculation, precipitation, and membrane chromatography are discussed. We also cover platform approaches to purification methods development, use of high throughput screening methods, and offer a view on future developments in purification methodology as applied to mAbs.

https://www.tandfonline.com/doi/pdf/10.4161/mabs.2.5.12645

Recovery and purification process development for monoclonal antibody production

Desalination by using reverse osmosis (RO) membranes has become very popular for producing freshwater from brackish water and seawater. Membrane lifetime and permeate flux, however, are primarily affected by the phenomena of concentration polarization and fouling at the membrane surface. The scope of the current paper was to critically review the literature on the fouling phenomena in RO and ultrafiltration (UF) membrane systems, the analytical techniques used to quantify fouling, preventive methods, and membrane cleaning strategies. The paper also makes specific recommendations on how scientists, engineers, and technical staff can assist in improving the performance of these systems through fundamental and applied research.

Fouling of Reverse Osmosis and Ultrafiltration Membranes: A Critical Review

Cross-flow filtration with microporous membranes is increasingly used in the separation and concentration of particulate suspensions. Existing models for the filtrate flux are inadequate for correlating experimental observations and are based on contradictory physical mechanisms. We propose that the flux is limited by the formation of a dynamic concentration polarization boundary layer consisting of a high concentration of retained particles. A simple model is developed incorporating a shear-enhanced diffusivity of the large particles which arises from mutually induced velocity fields in the shear flow of the concentrated suspension. Predictions of the model agree well with experimental data for a variety of particulate suspensions. The model provides both a fundamental understanding of the physical phenomena governing flux and a rational basis for design of improved cross-flow filters.

F.W. Altena

Papers

Lateral migration of spherical particles in porous flow channels: application to membrane filtration