Changes in the Extracellular Accumulation of Antibiotics during Growth and Sporulation of Bacillus subtilis in Liquid Culture

Ten antimicrobial metabolites, produced by Bacillus subtilis NCIB 8872, have been categorized into 3 groups on the basis of their antimicrobial spectra, chromatographic mobility and solvent solubility. The maximum concentration of the different groups occurred at different times during fermentation. The accumulation of one antibiotic group was characteristic of the logarithmic growth phase. Groups also differed in their persistence. The intracellular antibiotics contributed little to the total antibiotic activity of the culture. The onset of production and the maintenance of the extracellular accumulation of the 3 antibiotic groups were linked to sporulation and associated specific changes in the intracellular and extracellular protein complement. Production of the antibiotics was not controlled by glucose catabolite repression, since the presence or absence of glucose in the medium did not affect the pattern of antibiotic accumulation.