Introduction: In the lectures so far, we discussed the strategies to generate recombinant DNA and use them through over-expression in host system to produce biomolecule either in secreted form or inside the cell. The operation involved in isolation and purification of a product from a suitable organism to develop useful product is collectively known as down-stream processing (Figure 28.1). After the product is formed either in free (secreted) or associated with cell, the next process is to collect the product from cell. No specialized process is required to collect secreted product but several methods have been developed to released the product through cell disruption. Once the product is collected, additional extraction and purification steps are needed to develop final product for application.

Figure 28.1: An over-view of different steps in down-stream processing.