Plasmid stabilization of an Escherichia coli culture through cycling

The problem of plasmid instability of fermentations that involve plasmid-bearing recombinant organisms is dealt with in this work. Previous theoretical work demonstrated that under certain conditions (where plasmid-bearing species are slower in responding to changes in the fermentation environment than the wild species) the washout of the plasmid-bearing species can be prevented. In the sequel, Weber and San showed that cycling the dilution rate can delay the washout of plasmid-bearing species for a plasmid-bearing Escherichia coli culture. This work shows that it is indeed possible to secure the presence of the plasmid-bearing species at all times through appropriate cycling.