 As we have seen in our previous module that there are the different strategies which we can employ on the recovery and the purification of the product. But as concern the total economics of the purification steps then it may be possible to modify the handling characteristics of the broth. So that it can be handled faster with the simpler equipment making use of number of techniques. So what are those techniques? So the first technique is the selection of the microorganism which produce pigment or undesirable metaproils. So that just to indicate that where that microorganism. The second is that is the modification of the fermentation that reduce the production of metabolites which we called as unwanted metabolites. The third is having the precise timing of harvesting. So if there is a little bit inaccuracy then we can say that there is the addition of unwanted metabolites. As we know that when there is any growth, lag, log and stationary and then decline phase so depending upon that phase then the whole scenario of the fermentation change. So that is why the actual timing is very critical. So at what time that we have to harvest that. Then the pH control at the time of harvesting. So sometime it happens when we stop the upstreaming process then we not bother about the pH drift. So when there is a drift in pH then that can have the adverse effect on the nature of our product. And even sometimes the product is soluble just with the change in pH then that product will become soluble. So that having the hindrance and then can increase the cost of the harvesting. So then is the temperature treatment after harvesting. And then is the addition of fluctuating agents and then the use of the enzymes to attack the cell wall. So this is very important when the product is intracellular. So the recovery and the purification of many compounds may be achieved by a number of alternative routes. The decision to follow a particular route involves different circumstances. So the main factors which we have to focus that is the capital cost, processing cost, throughput requirement, yield potential, product quality, technical expertise available. So these are the different six factors which we have to focus while using the recovery and the purification route. So as concern the microorganism and other similar size particles that can be removed from the broad by using the centrifugation when filtration is not satisfactory separation method because as we know that the first step after the fermentation is the separation as we have seen in our previous module. So when we talk about the separation technique, so that the separation there is a two possible ways. One is the centrifugation and other is the filtration. So both has their pro and prongs. So as concern that when we use the using of the centrifuge when filtration is not satisfactory a separation method. So also the centrifuge may be expensive when compared with the filter process. So it may be essential when the filtration is low and difficult. So cell and the other suspended matters must be obtained free from the filter rates because sometimes when we use the filter then those particles either have attached to that filter fibers and sometime they hold that. So then that can sometime the filter etch out. So then there is the only possibility of the centrifugation. So the continuous separation to a high standard of the hydrogen is required in the centrifugation. So as concern this continuous centrifugation you can see here that the continuous centrifugation and we are continuously feeding to this and then the during the centrifugation the product and those particles that remain inside and then the broth comes out. So that is the basically the mechanism of basket centrifuge. So we can separate by using that is a little bit along with the centrifugation and the filtration techniques which we called as the basket centrifugation technique. So as concern you we can see that there is also a multi chambers centrifugation techniques. So these are different kind of the centrifugation techniques and centrifugation which we can apply on the just to separate the biomass and unsoluble particles depending upon their size depending upon their density as well. So when we separate the soluble fraction and insoluble fractions and depend upon that then is if the product is intracellular then we start the cell disruption. So as concern the cell disruption there are the different chemical methods and the physio mechanical methods. So as concern the chemical method that is the detergent, osmotic shock, alkali treatment, enzyme treatment as concern the physical and mechanical that is the liquid shear, solid shear, agitation with abrasive, freeze thaw, ultrasonication. So these are the methods which is mostly used for the cell disruption. So as concern when we say that when the cell is disrupted and we have the product and sometimes we have to drive that then sometimes we use the solvent extraction methods then sometimes there is a single unit which we use as you can see here this in this diagram a single stage extraction unit in which the different liquid phase and then there is a solvent different chemical methods on which apart from the centrifugation and other we can use, we can separate the filter broth fermented broth into two phases either organic phase and in organic phase so just on apply that. So the major item of the equipment in the extraction process is the solvent recovery plant which is usually is a distillation unit when we talk about the chemical recovery and then having the unit like that then the major equipment is the solvent recovery unit. So it is not normally essential to remove all the refinate the product which has the component removed from the solvent as this will be recycled through the system. So by using that different organic solvent and another inorganic solvent we have to separate and recover our desired product.