 మాడిన benevolent మాన సిన్మారడిటా ఇపరాష మ котором వారడిక౿లоки� మిమాసిక౿మాటి మతిలాటా మారడ౿మాసికిటిక౿లోం. So, as we see in previous module that during the fat batch flow rate and the dilution is very critical. So, at the time during the fermentation process as well as the time will progress, dilution rate will decrease or increased mean the addition rate the flow rate if the flow rate or the dilution increase and decrease that can be expressed by this equation as you see here. So, if the dilution rate will decrease as the volume increase and the d will be expressed by this equation d is equal to f is the flow rate and v naught is the initial volume in the fermentation valve cell when you we start the feeding. So, f t is the flow rate at that time. So, according to monod kinetics residual substrate should decrease as d decrease because if we set our feeding strategy according to the limiting substrate. So, we can easily say if dilution will decrease then the residual substrate will also increase so, resulting in an increase in the cell mass concentration. So, the if the mu will remain the same or we can say that mu and d is not equal and the mu is more than the d then there will be a more concentration inside the fermentation vessel. So, the overall we can say that the mu which will operate in fat batch and SR will be much larger than K s and we know that K s is the substrate utilization constant which we called as monod parameters. So, for all practical purposes the change in residual substrate concentration would be extremely small and may be considered as 0. So, thus provided that the d is less than mu max and K s is much smaller than SR. So, in this age the quasi steady state may be achieved. You have seen in this discussion that how the specific growth rate initial substrate concentration with respect to the K s. So, if we focus all these parameters during the fat batch then it can easily be said that that state which we produce that is known as quasi steady state. So, in this slide you can easily see that two different diagrams. As concerned the A this is that how different parameters can be affected in fixed volume. But in case of the B you can sorry A deal with the variable volume and B deal with the fixed volume. So, if we talk about the variable volume first. So, SNL these are the substrate concentration GLS growth limiting substrate mean those substrate which directly affect on the growth or on the fermentation process. But there are some substrate which have not directly effect on the fermentation process which here you can say represent as SN non limiting substrate and X is the biomass. So, during the variable volume and if we have the d is equal to mu and then we can say that first when we start the feeding that there is a small drift in the mu line and then it become constant. So, X remain the constant because our d is equal to mu. So, that always remain constant that only disturb when the dilution or a flow rate will be disturbed. So, SN because that only remain the constant because have no utilization or no effect on that and whole strategy of the feeding and fed batch depend upon those substrate which we called as GLS. So, by this graph you can easily see that how different parameters varied during fed batch in variable volume. But in case of this another diagram you can see that there is a constant decrease in a mu. But there is a constant increase in biomass concentration because when we are having the addition of the substrate and no change in the volume what happen the mu remain the same and there is a continuation addition of the extra biomass in the same volume. So, the overall concentration of that remain increasing. So, you can see that there is the same appearance of those substrates concentration which are growth limiting because our feeding strategy mostly focused upon this we can say that GLS growth limiting substrate. But in this case when we say that those substrate concentration that have decreasing rate because we are not adding that because we are adding those only become the limiting because those substrate which are not limiting there is no need to add and then their concentration gradually decreased. So, the major difference between the steady state of a chemostat and the quasi state of the fed batch culture is that mu is constant in the chemostat but decrease in the fed batch. Why that is decrease and why in a chemostat that remain constant. So, when we say that mu is equal to D. So, then there is no more change in the biomass concentration DX over DT is equal to 0 that only possible when we say that residual substrate is also 0. So, if we if there is any residual substrate we are adding in such a way that there is the increase in the residual substrate concentration then there is a gradually increase of those substrate. So, fed batch culture can only be run. So, the feeding can only be happened when there is a volume provision of the fermentation vessel. So, we know that the maximum volume of the fermentation vessel can be utilized 75 percent of the total volume suppose if the fermentation vessel is total having the 10 liter and we can maximum utilize the volume 7.5 liter because the head space is very critical that is needed for the gaseous exchange and some foam control etc.