Bacillus thuringensis is a bacteria having the capacity to produce an insecticidal protein called Bt toxin, which is crystalline, proteinaceous, insecticidal δ-endotoxin. This toxin is produced in the inactive form by the cry gene found in the bacterial genome. There are a number of them. cryIAc and cryIIAb control the cotton bollworm and cryIAb controls corn borer. These proteins are produced in inactive form so that the bacteria is not affected by it. When this protein comes in contact with the digestive juices of the gut of the insect, it becomes active. The activated protein bind to the surface of epithelial cells of midgut and create pores. These causes swelling and lysis of cells leading to death of the insect.

Thermus aquaticus is useful to obtain the Taq polymerase and E. coli is a prototype prokaryotic organism used for genetic studies. Streptomyces griseus is providing the antibiotic streptomycin.