ABSTRACT
Various genera of bacteria are able to survive adverse conditions through the formation of metabolically dormant endospores. As with the growth of all vegetative microorganisms, the nature of the medium influences many of the cellular properties. During the logarithmic phase, growth rates are determined by the nature of the ingredients in the medium, the incubation temperature, and the pH. Each of these factors will have some influence on the properties of endospores produced. Progression of the growth of the culture from logarithmic phase to stationary phase can be abrupt, where the depleted nutrient is essential and converted to cellular mass with low efficiency, or it might be extended over many hours. Grelet devised sporulation media in which each of the components in a defined medium was in turn made the growth-limiting factor while other components were present in excess. The sporulation and harvesting was extended substantially beyond the time required for liberation of free spores from sporangia.
