bioreactor studies of heterologous protein production by ...

close contact of immobikd ceiis may fkibte the unbiased partition of plasmids between
mother and daughter cells during ce1 division. Therefore, segregational plasniid 10s is iess
likely to happen in the imrnobilized ceil system.
The proposed mode1 successfuIly describes the experimental results and provides
useful infornation for better understanding the stabilizing rnechanism of the immobilized
recorn binant cells. It may be concluded that s reduced specific growth rate coupled with
an increased plasmid copy number is a general explanation for the enhuiced apparent
plasrnid stability in an irnmobilized cell system.
6.2-4. Efféct of Feeding Glucase Concentration
Using Mous inlet glucose feed concentrations (Go), continuous fermentation experiments
were also perfomed in the immobiüzed-cell-film bioreactor at dilution rate O. 1 h-'. Figure 6.9
is a cornparison of giucoamylase concentration between the fke and immo bikd ceil system rt
a feed glucose concentration Go = 10 gL. Again higher enzyme concentration and slower
decay rate of emyme production were observed wiih the immobilized cell system. The
enhanced effect of immobilitation on enzyme production was further connmied.
The etfect of the glucose fwd concentration on the emyme production in the
irnrnobilized ceil system is shown in Figure 6.10. As expected, the enzyme concentrations
inneased with inmashg glucose concentrations since higher ce1 concentrations was obtained
at higher giucose concentration ( see Figure 6.1 l and Table 62 ). Neariy panllel lines are