[The growth and sporulation of Bacillus subtilis under different aeration conditions]

The dynamics of accumulation of Bacillus subtilis 39 cells and spores under different conditions of aeration has been studied. It is shown possible to intensify the process of growth, biomass accumulation and sporulation of bacteria using aeration conditions. The growth of cells of the studied bacilli proceeds under conditions of providing the culture with oxygen according to its real demands for the whole period of fermentation. The mathematical models have been obtained which connect the aeration conditions with the rate of biomass accumulation and sporulation of the studied bacteria. It has been stated that with an increase of aeration the yield of microbic cells, degree of using the substrate by them as well as the specific growth rate become higher. Intensive aeration 4.4 = 5.8 g O2/l.h promotes the creation of the most optimal conditions for the growth of bacteria. While deteriorating the aeration to 3.2 g O2/l.h and over, the specific growth rate and yield of viable cells decrease. The optimal conditions of air feed and medium agitation rate decrease the duration of fermentation exerting no effect on the final yield of biomass. It is shown that yield of biomass and spores depends on the growth phase.