 In this module we will again talk about the downstreaming process as we already discussed in our first module that depend upon the localization of the product we have to proceed our recovery and purification steps. As concerned the processing equipments must be therefore be of the correct type and also the correct size to ensure the harvest broth can be processed within the satisfactory time. So, the selection of the equipment and their size and all the things that should be according to the fermentation capacity and fermentation volume. So, the choice of the recovery process is based on the criteria. So the first criteria is that I have already told you that the localization of the product either the product is intracellular or extracellular actual the location of the product in the fermented broth. The second is the concentration of the product in fermentation broth this is very critical. So when there is a upstreaming movement during the upstreaming process time by time we check our the concentration of our product with respect to the biomass in order to calculate the different kinetic parameters, but at the end when we stop the upstreaming process then we should know that what is the actual concentration of the product. And the third one is the physical and the chemical properties of the desired product as an aid to select the separation procedure because if we know the chemical and the physical nature of the product then we can proceed further for the separation techniques. And the fourth is intended use of the product. So what is the use of that product either that is used in the food product either that is used in some human use or that is used in some pharmaceutical products depending upon that where that product has to be used. The fifth is the minimal acceptable standard of the purity. So we should know that what is the acceptable purity standard in the market. The sixth the magnitude of the bio hazards of the product or the broth very critical because this criteria is directly linked with the containment level of the fermentation process. Once that we have checked the risk associated with the process organism on other hand the product if that product is also having some bio hazards we should continue our recovery process accordingly. The seventh is the impurity in the fermented broth that how much possible impurities can be. The eighth is the marketable price of the product. So if the processing cost of that product is very high and we cannot compete in the market then the whole process of the fermentation was useless. So the main objective of the first stage for the recovery of an extra seller product is the removal of the large solid particles and microbial cells usually by centrifugation or filtration as you can see in the next slide. So this is the strategy started from the fermented broth and then the removal of the solids if the product is intracellular then the cell disruption has to otherwise if the product is extra seller then there is a primary isolation and then purification and the concentration which we called as the scanty process and tertiary process and then is the final product isolation and then packaging and then control the self life. So these are the different stages that we have to follow according to the localization of the product. So in the next stage the broth is fractionated or extracted into the major fractions using ultrafiltration, reverse osmosis, adsorption, ion exchange, gel chromatography, liquid liquid separation, two phase aqueous extraction and precipitation. These are the different techniques which we can use for the purification of the product depending upon the physical and the chemical properties of that product. So afterward the product containing fraction is purified by the fractional precipitation furthermore precise chromatographic techniques and the crystallization which is to be obtained for a highly purified forms essentially free from a minor impurities. So other products are isolated which we called as the by products that can be aid to the fermentation economics that we discuss later on. So ultimately when we talk about the purification and isolation strategies of the product we have to keep in mind the different available strategies depend upon the chemical and the physical nature of the product.