 In this module, we will talk about the foam control system in fermentation process or in a fermenter while talking about the fermenter design. Foam control is an essential element of the operation of a sparse bioreactor. So, in case of the mixing, agitation system and oxygen delivery system associate to each other when they work and the process is going on then what happen then depend upon the nature of the medium what happen the foam will produce. As you can see in this picture that the head space is totally filled by the foam just this is just an example of two-liter laboratory actor. So, if in such case when there is a condition when foam is produced the production of foam can effect on the oxygen solubility on one point and the second the existence of the foam that also make the column and then there is a loss of the fermentation medium to the exact air point. So, the excessive foam formation when that tend to go from the exact point that can choke the air sterilization system which we called as the filter. So, in such case then there is any disturbance so that can cause any pressure inside that so there are so many happening that can happen. So, in little case we can do that we use when there is no blockage either there is removal of that and when we have no any direct manual look in what happen then there is gradually loss of the medium and then we cannot have some in case in the absence of the operating personnel then there is a risk. So, to avoid this risk in case of the foam then the foam has to be controlled. The foam can be controlled by the addition of some chemicals so the chemicals having a two type of nature one is anti foaming properties and other has the deformer properties. So, some chemicals known as the anti foams mean they hindered the production of the foam. So we add some anti foaming agents before the formation of the foam so when there is a foam produce and then we can add some deformers but commonly the word is anti foam is used. So, if we add a suitable anti foam but there is very critical while having selecting and the choice of the anti foams. In later module we will talk about that what will be the quality of the anti foams because anti foam has to directly enter into the fermentation medium that can have the toxic effect on the organism as well as mostly the anti foams can also effect on the oxygen solubility. So that is why we have to very careful about selecting the anti foams which we will talk about in our later module.