Separation, concentration and purification of the product
Bioseparation and purification during downstream processing have been achieved through techniques, which can be classified into two groups: (i) chromatographic methods; (ii) non-chromatographic methods. The chromatographic methods, which include a variety of techniques, give better resolution, but are expensive and more difficult scale up. These have been briefly described. In contrast, the non-chromatographic methods are relatively cheap and easy to scale up; these methods are, therefore, preferred for the downstream processing of industrial products. Some of the non-chromatographic methods, which gained popularity in recent years include electrophoresis, affinophoresis, affinity ultrafiltration, affinity precipitation, three phase partitioning and expanded bed chromatography. These are briefly discussed in the following text, which is based on an article published in PINSA Part B (April 2002).