Bioprocess Engineering 2nd Edition by Fikret Kargi,Michael Shuler

Exercise 16

Consider the case of two enzymes immobilized on the same nonporous, planar surface. S is a
substrate used by both enzymes in the following reactions: and The final product P3 is formed by the spontaneous reaction of P1 and P2: Reactions 1 and 2 occur only at the surface and reaction 3 is a homogeneous reaction occurring
throughout the bulk liquid phase.
Figure 3.P2 gives the predicted reaction-rate dependence of reaction 1 (bottom curve) alone
and reaction 2 (top curve) alone based on the measured amount of each enzyme immobilized and
assuming the intrinsic reaction kinetics are not altered in the process of immobilization.
a.
cm/s and the bulk concentration of substrate is 500 mg/l, what is the total rate of
substrate disappearance?
b. What is the overall effectiveness factor under the conditions of part a?
c. What will be the ratio of P2 to P1 under the conditions of part a?
d. If you want to produce equimolar amounts of P1 and P2 and if
what value of
bulk substrate concentration must you pick?