Enzymes - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 361

F S0 , S 0 = 1 M, E 0

F S , F P = 100 moles/h
S , P, E 0

FIGURE E8-3 Well-mixed reaction vessel.

Thus, the rate of formation of P is given by

S
K m þ

k E

0

r P ¼ (E8-3.2)

S

min 1 =ð0:1 L $ min 1 $ g 1 :

K m ¼ 0:01 mo 1= L and k ¼ 0:15 g = L Þ¼1:5

(b) It is understood that the CSTR is operating under constant temperature (isothermal) and
steady-state conditions, i.e. no accumulation of any sort of materials inside the reactor.
Mole balance around the reactor for P yields

0F P þ r p V ¼ 0 (E8-3.3)

Substituting Eqn (E8-3.2) into Eqn (E8-3.3) , we obtain

F P

r P ¼ F P K m þ

S

V ¼ (E8-3.4)

k E S

0

(c) Based on the economic information at hand, we can estimate the gross profit for the
reaction process as

GP$ ¼ $ P F P $ S F S 0 $ E F E 0 $ v V (8-3.5)

where $ P ,$ S ,$ E , and $ V are the molar value of product P, molar cost of substrate S, unit cost of
enzyme, and the unit operating cost of reactor based on the reactor volume and time,
respectively.
Based on the stoichiometry, we have

F P F P

Q ¼

P ¼

(E8-3.6)

S

0

S

which leads to