Study of the sporulation of Bacillus thuringiensis var. thuringiensis.

During the submerged cultivation of Bacillus thuringiensis var. thuringiensis in 300- and 3000-liter fermentors, lysis occurred at the end of the exponential phase of growth. New vegetative cells were subsequently formed which usually sporulated. At time of lysis, the amount of soluble sugar was 1-12 g/liter, pH value dropped to 5.3-5.8 from the original PH 6.8 and started to rise after all the cells had lysed. The proteolytic activity was low during the lysis and increased as the sporulation commenced.