Downstream processing involves various techniques which are used for the sake of recovery or removal of products.
Some of its techniques are:
- Cell Disruption: Various products included in downstream processing involve many proteins and enzymes to destroy the cell and discharge of these products the example of which is yeast. This process can be accomplished by two methods; mechanical and non-mechanical. In the mechanical method, liquid shear homogenization and sonication occurs while in the non-mechanical methods, osmosis, autolysis, shock etc. are present.
- Elimination of insoluble products, splitting-up of the cells, debris or other particulate stuffof the cell from fermentation broth culture.
- Filtration: Separation of constituents from the liquid just by application of pressure to the liquid solution to coerce it via a filter. These filters include pores. If the constituents have size larger than the size of the pores then they are accumulated on the top of the filter while the constituents of the smaller size pass through these pores accompanying the liquid and can be collected easily.
- Processes like ultrafiltration, reverse osmosis, microfiltration and nano-filtration are also done.
- Centrifugation: It is used when there is a requirement of separating the particles which are of size greater than 0.1μm diameter and is appropriate for separations which involve only liquids. Ultracentrifugation is the high speed centrifugation which is needed for the segregation of smaller constituents.
- Disc stack centrifuge is also a useful technique.
- Coagulation: It involves the formation of semisolid lumps in the liquid solution. The flocculation coagulation involves the production of woolly cloudlike accumulations.
- Product Purification: This technique involves the removal of particles having characteristics identical to those of the actual products. Chromatography is another technique useful for the separation of molecules on the basis of their physical and chemical properties.