Advances in product release strategies and impact on bioprocess design

Intracellular products such as recombinant insulin, which are typically produced in microbial host cells, demand a product release step to remove them from the cell. How this is performed determines the quantity of released contaminants, the particle size distribution of cell debris and the physical properties of the resultant process stream, which all impact on the performance of the downstream operations. Thus, achieving selective release of the desired product is crucial for improving the process economics. Advances in upstream processing (the bioreactor phase) have been successful in achieving high product titres, and downstream costs now typically dominate the overall manufacturing costs. Here, we review and discuss the selective release of products as a possible means of improving the efficiency of downstream processing.