This microbe is a member of the Bacillus cereus family, which includes B. anthracis, B. cereus, and B. megaterium. These are Gram positive endospore-forming rods belonging to the Group 1a Bacilli known for oblong spores that do not distend the sporangium. They are catalase positive and ferment carbohydrates without production of gas. They grow well over a wide range of temperatures.
Bacillus thuringiensis is most famous as an insect pathogen capable of selectively killing larvae of several insect Orders, including those of insect pests responsible for crop damage (caterpillars and borers) and transmission of disease (mosquitos). During sporulation, Bt (as it is known) produces a protein crystal that dissolves in the larval gut to release a potent toxin. Commercial products comprised of crystal proteins are available as “bio-safe pesticides, and genes for the toxic proteins have been engineered into crop plants to reduce crop loss from target insects.