includes all steps of purifying a product. It consists of three steps: (1) the separation, (2) the enrichment and (3) the purification. In the first step, the crude product is separated from the biomass or cellular mass and other solids. Thereby, it has to be considered that the product can be present either intra- or extracellular. An intracellular product requires a previous disruption of the cells. The separation can then be carried out via centrifugation, precipitation or filtration (see filtrations). This is followed by water removal in order to enrich the product. Common procedures to eliminate water are reverse osmosis, adsorption and extraction methods. For subsequent product purification, chromatographic methods (see chromatography) are used. Virus removal, as well as the final formulation and filling of the purified product, also belong to the area of DSP.