Bacillus
Last reviewed 01/2018
The Bacillus genus are typically Gram-positive bacilli. It includes Bacillus anthracis which causes anthrax, and Bacillus cereus which causes food poisoning.
Morphologically, Bacillus is characterised by spore-bearing rods which are generally Gram-positive in fresh growth. When nutrients are sparse, spores production becomes more prevalent. However, under certain conditions Bacillus may form occasional Gram-negative rods which align into long chains. The latter also may have flagella and hence motility.
Bacillus grows in an aerobic environment on nutrient agar over a wide range of temperatures (20 to 50 degrees centigrade). Biochemically, it produces catalase and proteases which liquify gelatin.
Classification is based upon the position, size and shape of spores as well as the products of glucose fermentation.