Bacillus thuringiensis (or
Bt) is a
Gram-positive, soil-dwelling
bacterium, the most commonly used
biological pesticide worldwide.
B. thuringiensis also occurs naturally in the gut of
caterpillars of various types of
moths and
butterflies, as well on leaf surfaces, aquatic environments, animal feces, insect-rich environments, and flour mills and grain-storage facilities
During
sporulation, many Bt strains produce
crystal proteins (proteinaceous inclusions), called
delta endotoxins, that have
insecticidal action. This has led to their use as insecticides, and more recently to
genetically modified crops using Bt genes. Many crystal-producing Bt
strains, though, do not have insecticidal properties.
As a toxic mechanism,
cry proteins bind to specific receptors on the membranes of mid-gut (
epithelial) cells of the targeted pests, resulting in their rupture. Other organisms (including humans, other animals and non-targeted insects) that lack the appropriate receptors in their gut cannot be affected by the
cry protein, and therefore are not affected by Bt.
Currently I use; for this purpose.
bacillus licheniformis
bacillus azotoformans
bacillus megaterium
bacillus coagulans
bacillus pumilus
bacillus thuringiensis
It's always good to have some redundancy built in, if possible, as environmental conditions, culture counts are going to vary by subspecies.
