Bacillus subtilis forms endospores and is a major model organism in bacterial biology, but Ferdinand Cohn’s classic endospore work concerned Bacillus subtilis and related bacilli.
B. subtilis is a Gram-positive, rod-shaped soil bacterium that can form a highly resistant endospore when nutrients become scarce. The endospore is a dormant survival structure, not a reproductive cell. It protects the bacterial DNA and essential components from heat, drying, and other stresses.
The species has been studied extensively for cell division, secretion, motility, development, and gene regulation. Its ability to secrete proteins also makes it useful in biotechnology and enzyme production. Ferdinand Cohn’s nineteenth-century studies of bacterial spores helped demonstrate that bacteria were distinct organisms rather than simply stages of fungal growth.
B. subtilis is often confused with Bacillus anthracis, the cause of anthrax. Both are spore-forming bacilli, but they differ in disease relevance, morphology, and laboratory characteristics.