Bacillus thuringiensis

Bacillus thuringiensis (or Bt) is a gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide. Alternatively, the cry toxins may be extracted and used as a pesticides.

During sporulation, many Bt strains produce crystal proteins, called δ-endotoxins, that have insecticidal action. This has led to their use as insecticides, and more recently to genetically modified crops using Bt genes.