 In this module, we will talk about the downstreaming process of the fermentation process. As the introductory lecture about the fermentation process, when we define the fermentation we said that it is the mass culturing of the microorganism for the sake of desired product. For this definition in which we use microorganism and then we cultures those organisms or microorganism just for the sake of any product. So, the culturing of the organism and in order to produce the product as we earlier stated in our previous modules that this whole process comprises two major steps. First one that is known as upstreaming process and the second one is known as downstreaming process. In upstreaming process as we know that start from the stock culture up to the production vessel and the in which we culture and then we produce any product. Let us concern the downstreaming process that comprises the recovery and the purification of the product. So, let us start what is the recovery and the purification of the fermentation products. The extraction and the purification of the fermentation products may be difficult and costly. Ideally one tries to obtain a high quality product as quickly as possible at an efficient recovery rate using minimum plant investment operated at minimal cost. Unfortunately, the recovery cost of the microbial products may vary from as low as 15 percent to as high as 70 percent of the total manufacturing cost. If a fermentation broth is analyzed at the time of the harvesting it will be discovered that the specific product may be present at a low concentration in an aqueous solution. That contains intact microorganisms, cell fragments, soluble and insoluble media components and other metabolic products. Because during the fermentation process when the microorganism grow depend upon the nature of the product that can be the biomass then if the product is any metabolites or any enzymes then the product might be intracellular or extracellular. So, when the product is intracellular then the strategy for the recovery and the purification process is the different than if the product is extracellular. So, along with others then that contain if the product is extracellular then that contain the intact microorganisms, cell fragments as you know that these are the different which contain in a fermented broth. So, the product may also be intracellular, heat labile and easy broken down by contaminating microorganism. So, when you start the recovery and the purification process then we cannot maintain the aseptic conditions as we can keep during the fermentation process. So, all these factors tend to increase the difficulty for the product recovery. So, to ensure the good recovery of the purification and the speed of the operation may be the overriding factor because of the liable nature of the product. So, for the selection of the recovery and the purification steps we have to be very careful. Our product will not be lost during the recovery process and the cost of the purification recovery and the purification that should not be exceed. So, we have to be very careful while starting and while selecting the down steaming process.