bioreactor studies of heterologous protein production by ...

Table 6.1. Measured and Predicted First-Order Decay Constants in hmoblued
Cell Systems at Different Düution Rates.
xi Cc)
Predicted p, (h")
'~easured ki (h")
Predicted ki (I-')
Measured yl (a')
Predicted yi (VI)
L
7.72
0.04 12
0.003 1
0.0022
0.0038
5.83
0.0803
0.0089
0.0049
0.0 128
0.004 1 0.0090
* fust-order plasmid los constant of the suspended ce11 in the irnrnobilized celi system
It was reponed that segegaaonal plasmid instability increases with increasing
specific growth rate in culture of recombinant yeast in nonselective medium (Hardjito et
al.. 1993; hpoolsup et al., 1989b). Sirnilar 'observation cm be made for the present
raornbimnt stmin (Figure 5.8): the more the cells &5cie, the more &&y they lose plasmi&
Therefore. an reduced specific growth may be responsible for the improved apparent
plasmid stability in an immobilized celï system. Assuming an identicai pmbability of
plasmid loss for both free and irnmobilizd ceD systems, the apparent fmt-order decay
constants for plasmid los and enzyme production in the immobilued ceii system can be