Spore formation by Bacillus popilliae in liquid medium containing activated carbon

Haynes, W. C. (Northern Regional Research Laboratory, Peoria, Ill.), and Lenora J. Rhodes. Spore formation by Bacillus popilliae in liquid medium containing activated carbon. J. Bacteriol. 91:2270-2274. 1966.-Heretofore, it has not been found possible to evoke sporulation of Bacillus popilliae in liquid culture. We have discovered that sporulation will occur in tryptone-glucose-yeast extract broth shaken cultures if activated carbon (charcoal) is present during growth. The spores so engendered have survived drying in air and subsequent storage for several months as dry films and also in dry soil, sand, and a mixture of powdered calcium carbonate and talc. Furthermore, the longevity of cultures, even when spores are absent, is extended, in cultures containing activated carbon, to several weeks at a population of millions of cells per milliliter. This extension of life is the result of a marked change from rapid decline in numbers to an almost stationary population.