Medium design for plasmid DNA production based on stoichiometric model

A medium for culturing Escherichia coli JM109 pcDNA3S as a DNA Vaccine was developed using a stoichiometric model. In batch fermentation, using the de signed medium MWI and MW2, the plasmid DNA yield was 60 +/- 5.0 and 30 +/- 4.0 mg/l, respectively. However, plasmid the DNA yield was only 4 +/- 0.4 m g/l in LB medium and 20 +/- 3.5 mg/l in LEG medium. The plasmid stability c haracteristics of the JM109 pcDNA3S grown in LB, LEG, MWI and MW2 were dete rmined in continuous cultures. After 96 h cultivation, the plasmid stabilit y was 11.3% higher when bacteria were cultivated in MW1 medium relative to cell growth in MW2 medium, 30.6% higher relative to cell growth in LB mediu m, 63.3% higher relative to cell growth in LEG medium. These results show t hat amino acids and nucleosides affect plasmid DNA yield significantly. It seems that the defined medium can support much higher plasmid DNA yield tha n a complex medium. Amino acids and nucleosides are important factors to be considered during production of plasmid DNA. (C) 2001 Elsevier Science Ltd . All rights reserved.