Recombinant beta-glucanase production and plasmid stability of Bacillus subtilis in cyclic fed batch culture

Recombinant beta-glucanase production and plasmid stability were higher in cyclic fed batch culture than in batch and chemostat culture. Plasmid stability was maintained indefinitely in cyclic fed batch cultures of Bacillus subtilis when subjected to cycle periods of 2 or 4 hours. Cycle periods greater than 6 hours resulted in loss of the plasmid. In batch and chemostat cultures plasmid loss was rapid. beta-1,3-glucanase productivity was highest in cyclic fed batch culture.