Downstream processing in the biotechnology industry.

The biotechnology industry today employs recombinant bacteria, mammalian cells, and transgenic animals for the production of high-value therapeutic proteins. This article reviews the techniques employed in this industry for the recovery of these products. The methods reviewed extend from the centrifugation and membrane filtration for the initial clarification of crude culture media to the final purification of the products by a variety of membrane-based and chromatographic methods. The subject of process validation including validation of the removal of bacterial and viral contaminants from the final products is also discussed with special reference to the latest regulatory guidelines.