The Minimal Nutritional Requirements of Some Species in the Genus Bacillus

Summary: The characteristic nutritional patterns were determined for seven species or varieties of the genus Bacillus. Six strains of Bacillus cereus var. anthracis grew in a complex but defined amino acid medium + thiamine. Three strains of the insect pathogen B. cereus var. thuringiensis had the same nutritional pattern as the parent species B. cereus and grew in a seven amino acid medium. Of twenty strains of B. firmus, ten grew on the seven amino acid medium + biotin while the growth of five other strains was markedly affected by the addition of thiamine. Two of the remaining five strains required thiamine on first isolation, but soon dispensed with it on subculture, while the other three strains continued to require thiamine. Six strains of B. lentus grew in the seven amino acid medium + biotin + thiamine + urea. When the seven amino acid medium was replaced by the complex amino acid medium three of these strains of B. lentus grew without the addition of urea, and the remaining three strains required either urea or ammonium chloride. The sixteen strains of B. coagulans all grew in the complex amino acid medium + biotin + thiamine. The three strains of B. pulvifaciens grew in the seven amino acid medium + biotin.

The twenty-seven strains of Bacillus circulans formed a nutritionally heterogeneous group. Eight strains were maintained in serial subculture in broth but could not be grown in defined media. One strain grew in the ammonia basal medium alone, others required added biotin or added biotin + thiamine and others required amino acid media + biotin + thiamine.