 In this module, we will talk about the second important feature of state fermentor. While talking about the basic part of a state fermentor, in that module we have seen that body vessel, agitator or agitation system and a sparser. These three are the basic component of a fermentor except we are not talking about the accessories of an fermentor. We are talking about those part or those component which are directly attached in a fermentor. So, body vessel of the fermentor, we know that as our main body is, so the arms and head and the legs are attached to H and the same way a fermentor or a body vessel is the main and then there is agitation or agitator system that attached to the body vessel. That is a very basic part of a component of a state fermentor as the name indicates the steering is needed because when we have to run our fermentation process in a deep cultivation then there is a need of steering. So, you can see here that what is the function of the agitation system. So, agitation system provide good mixing. So, in case of the good mixing, then there is increase mass transfer. What is mass transfer? Mass transfer can be talk about in the liquid and the bubble boundary layers. So, when we talk about the agitation that provide the equal contact chance of the medium ingredient to the organism or we can say that organism has the equal chance to go anywhere in the fermentor vessel having the chance of utilization of the fermentation component or ingredient or a nutrients by the same way. If there is no steering though no proper mixing then what happened? Then there is a depletion of the nutrient surrounding the organism. So, on one side there is a depletion of surrounding and the same there will be the concentration of the secretions which can cause the toxic environment to that organism. So, when we talk about the good mixing that have the effect on the mass transfer mean that have the good for the transfer of toxic element out of the environment from that effect on that have the positive effect to dilute the toxic effect on other hand that have the chance of other nutrient to come closer to the organism. So, that on other hand it also provide the appropriate shear that requires the breaking of the bubbles. So, when there is a sparser and the air bubbles has to oozes out in the fermentation media agitation system separate those bubbles into a small bubbles. So, as the bubble size decrease then there will be a more surface area then there will be a more surface area then there will be a more chance of the oxygen solubility in the medium that ultimately effect on the metabolic process of the organism. As concerned the agitation system that consists of an agitator and the baffle. So, there are the two component of the agitation system one is agitator and other is the baffle. So, baffles not attached to the agitation system but that is the part of the agitation system. So, what baffles do I will talk about here that the baffles are used to break the liquid flow to increase the turbulence and mixing efficiency. So, as we have seen in our daily life and we making up any syrup in our home either milkshake etc., etc. Just look into the bowl of that there is a in growth. So, that in growth are basically known as the baffles sometime we put the spoon inside that just to make the more turbulence. So, if there will be a no baffle what happened there will be a continuous layering of that medium. So, the medium which have on a periphery that remain on a periphery and that medium that is on a in a center that remain in a center. So baffles actually gave the equal chance of the medium to come in contact from the outside to inside and inside to outside so that is only due to the increase in the turbulence. So, in this slide you can see that one part is the baffles and other is the agitator. So, as concerned the agitator that one part is the impeller. So, that can be a one impeller that can be two three it depend upon the size of the fermenter and the design of the fermenter that how many impellers are attached to the shaft. This is the shaft and then there is a motor and motor we know that motor has to drive this whole system along with this there is a sensor that sense this speed of the motor by which we have to control the rpm of the agitation. So, link of this agitation system that is through the seal as I have told you in our previous module that seal is very critical because there is a continuous process of agitation in case of that seal is very critical. So, this system if the seal is not good then there is a chance of contamination in case of good seal then we have a good and reliable agitation system.