Cell competence and membrane protein production in perturbed cultures of B. subtilis

The work presents a comparison of three different cultivation methods used to stimulate competence in Bacillus subtilis cells. The level of cell competence achieved under forced perturbations in cyclic fed-batch culture, was compared to competence achieved under steady state conditions in chemostat culture and under transient conditions in batch culture. The percentage of competent cells found using cyclic fed-batch culture was highest with a maximum value of 4.9% transformed cells obtained. Transient conditions achieved in batch culture resulted in a maximum value of 3.9% transformed cells. In chemostat culture, at steady state, a maximum value of 2.9% transformed cells was reached. Cyclic fed-batch culture was shown to induce a greater number membrane proteins in comparison to the membrane proteins produced under both batch and chemostat culture conditions.