Fed-Batch Bioproduction of Spectinomycin
45
Activation-Reaction-Inhibition model
tinomycin are,
for the fed-batch production of specdC
( Ke S )
C dV
dPa
(__Kel
S )C_KdPl_P-21d~ V
d---~- = al/tp,exp
S
Kil
V dt
dP2
( Ke2
S )C__KaP2 P2 dV
d--~ = ~2 ~P2 exp -- S
Ki2
- -
-V d--T
dt - Yc~s o~ I~m exp 9 S Ki
YPxs cq #e~ exp
S
Ki~
1
( Ke2 S )
Sv SdV
- Ye2--~s ~2 ,ups exp
S
Ki2 C + -~ -- V d~
dV
-- = F
(A.7)
dt
Here a, ~x, and a2 are the activation components. The maximum specific growth
rate is Pro, and/~p, and/~,, the maximum specific product formation rates for
P1 and P2. Also Ke and Ki are the exponential model and the inhibition
constants for cell growth; whereas Kel, K,I and Ke2, Ki2 are exponential model
and inhibition constants for P~ and P2, respectively.
The activation terms are constant for the process and act as a trigger to
describe the change from lag phase to growth phase. They have the form
exp(a(S - b)/(1 + exp(a(S - b)). The two parameters a and b need to be evaluated only once, so that they match with the start of spectinomycin synthesis. In
subsequent estimation of the model parameters, a is simply treated as a constant
premultiplier. In this sense, it does not belong to the set of model parameters
evaluated by nonlinear regression. The estimation model parameters are presented in Table 2.
11 References
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