Ultrafiltration and Crossflow Microfiltration Filtration

Abstract

The application of ultrafiltration (UF) in biopharmaceuticals is a constantly shifting landscape. Modern UF membranes have their origins in the 1950s when commercially viable reverse osmosis membranes were developed for water desalination. The consequence of protein fouling is the formation of a protein gel that irreversibly adheres to the membrane surface. These protein gels become secondary membranes that have protein rejection characteristics that mask the intrinsic properties of the membrane. Fractionation may be described as a separation process where one of the solutes is separated or fractionated, one from the other by means of passing the smaller solute through the membrane while retaining the larger solute in the feed solution. Crossflow filtration, as a primary separation process, is especially well suited for the harvesting whole cells from a fermenter or bioreactor prior to further downstream processing. The use of screens or meshes as static mixers in-between membranes are found in variety of crossflow devices.