Microscopic Studies of Endospore and Parasporal Crystal In Bacillus Thuringiensis Kurstaki A3-4 From Fermentor

Abstract Using microbes for the biological control of pests is progressing very rapidly. Because of the high specificity and none of toxicity to the vertebrates, they become the environmental biopesticides. The most commonly used entomopathogen is Bacillus bacteria, such as B. thuringiensis.Mass culturing of B. thuringiensisin different types of fermentor is experimenting in order to reach the highest yield of endospore and the crystalline endotoxin, the main virulent components for the pesticidal activity. Bacillus thuringiensisproduces endospore and the parasporal inclusions, Hannay (1953) observed in bacterium B. thuringiensis a mature endospore and a prism-shaped crystal (parasporal crystal).’ The endospore and the endotoxin crystal vary during growth depending upon the availability of nutrient. Glucose concentration in medium has enormous effects on the production of parasporal crystal, B. thuringiensiscan not grow, nor produce parasporal crystal in low concentration of glucose medium. The formation time of the endotoxin crystal also differs in different subspecies.