Question

The production of yogurts is carried out by adding a specific strain of bacteria to pasteurised milk. The bacteria consumes lactose in the milk to produce lactic acid. Assume the fermentation reaction can be simplified by the following reaction:

Lactose (A) + bacteria cells (C) à more bacteria cells (C) + lactic acid (R)

The data below shows the concentration of lactose from a 2 L mixed flow reactor at 40 ^oC.

Table 1: Experimental data for lactic acid fermentation

ѵ (L/min)	Clactose ( mg/L)
0.2	5
0.55	20
0.86	60
1.0	150

1. Show that the data fits substrate limited Monod Kinetics. Find the k and C_M values. Show your plot to obtain the kinetics values.
2. What is the highest rate of reaction of A (-r_A) when C_A0 = 4 mg/L, C_C0= 0 and C/A = 3.
3. Determine the concentration of cell C_C that can be produced using

a 100 L mixed flow reactor (MFR) operating at optimum condition for an inlet flowrate of 5 L/min. Sketch your reactor scheme (i.e. show whether there is a need to by pass and by how much)

Answer 1

using given data and mass balance on MFR we can find the required variables

for any doubts write in comments