A genetically modified yeast is cultivated at pH = 3.3 and temperature = 37°C). Values of substrate flow, F, cell mass concentration, X_{1}, concentration of glucose, S_{1} (the limiting substrate component), and product concentration, P_{1}, was measures throughout fermentation. The product is a protein  not a primary metabolite  and the substrate utilization for product formation, rS = Y_{X/P,stoich} × q_{p }× X, is so low that it can be neglected. All samples were taken after steady state had been established. The feed stream, S_{0}, contains 50.0 g glu/l and no product (P_{0 }= 0), and the working volume, V, is 500 ml. k_{e} = k_{d} = 0.
F (ml/h)

50

100

150

200

250

300

X_{1 }(g DCM/l)

17.7

21.5

23.2

24.0

24.5

24.0

S_{1} (g glu/l)

0.036

0.089

0.171

0.320

0.667

2.40

P_{1} (mg prod/l)

115

75

58

48

42

36

a. Explain k_{e} and k_{d}.
b. Examine if the growth if following Monod kinetics and if this is the case determine K_{S} and m_{MAX}.
c. Examine if the substrate utilization kinetics can be expressed by growth constants Y_{X/S,true} and m_{S} and if this is the case calculate these constants.
d. At D=0.46 h^{1} and same conditions as given above calculate Y_{X/S}, r_{X}, r_{S}, r_{P}, and Y_{P/S}.