Vol. 11, Special Issue 2 (2022)

Author(s):
S Archana Devi, K Devaki, M Rajasri and MK Jyothsna

Abstract:
In the present study B. thuringiensis was isolated from the soil samplesof cruciferous vegetable growing areas in Andhra Pradesh, using sodium acetate selection method. The soil samples were buffered with 0.5M sodium acetate followed by heat shock at 80 ^oC and serial diluted up to 10^-5 for eliminating non-spore forming bacteria and other microbes in the culture and then grown on LBA medium. After 24 hr of incubation, the colonies which were round, creamish with fried-egg appearance were produced. A total of 38 colonies from 50 soil samples were tested for Gram staining and observed 37 Gram positive bacteria with rod shaped structure. These 37 Gram positive cultures resulted in 22 endospore producing cultures and finally 15 crystal producing B. thuringiensis cultures were identified. Only bipyramidal types of crystalline inclusions were observed in the 15 new isolates of B. thuringiensis.