Effect of growth environment on the stability of a recombinant shuttle plasmid, pCPPS-31, in Escherichia coli

The effect of environmental growth conditions on the segregational stability of a recombinant Escherichia coli-Bacillus subtilis shuttle plasmid pCPPS-31 which expresses carboxymethyl cellulase (CMCase) and contains the neomycin resistance gene (Ner), was studied in E. coli DH5 alpha. The stability increased with the decrease in medium complexity. Lowering culture temperatures had a negative effect on stability. Stability was maximum at 100 rpm and a medium/flask volume ratio of 1:10. A pH range of 5-8 had no significant effect on stability. The recombination (rec) and gyrase (gyr) backgrounds of E. coli hosts had no apparent effect on plasmid stability. The plasmid was structurally stable under all circumstances.