Bacillus megaterium is a gram positive, endospore forming, rod shaped bacteria. It is considered aerobic. It is found in soil and considered a saprophyte.
Bacillus megaterium is latin for the big beast because it is an extremely large bacteria, it is about 100 times as large as E. coli. Due to its immense size, about 60 micrometers cubed, B. megaterium has been used to study structure, protein localization and membranes of bacteria since the 1950’s. Most notably, B. megaterium is the organism that was used by Lwoff and Guttman in the studies that discovered lysogeny.