bioreactor studies of heterologous protein production by ...

nonse1ective agar plates, but only the plasmid-beariag cells can grow on YNB selective
agar plates. The proportion of plasmid-bearing ceiis wue found by counting the colonies
on both types of plates (100-250 colonies per plate).
3.3-6. Mednation of Maximum Specific Growth Rates
The maximum specific growth rates of plasmid-fiee and plasmid-bearing were determined
using the wash-out method:
At one fned dilution rate (D > p,,,,J, p- can be found h m semilogarithmic plots of ceil
concentration versus tirne. Batch exponential growth was ais0 used to determine the
maximum specific growth rates.
3-4. Free Suspension Culture
The objectives of free suspension culture experiments were as follows:
1) To gain knowledge about the behaviour of the mode1 mombinant yeast (growth
characteristics. plasmid stability. recombinant protein productivity, etc.).
2) To investigate the effm of fermentation conditions, growth rates and growth media
on plasmid stability and recombinant protein production.
3) To examine the importance of the metabolic pathways in yeast with regard to
recombinant protein formation.
4) To obtain the parameters required for mathematical modehg.