Occurrence of Bacillus thuringiensis in faeces of herbivorous farm animals
Bacillus thuringiensis (Berliner), the insect pathogen has been isolated from a variety of habitat. It is understood that the habitat of B. thuringiensis has always been associated with their biological activity. In the present study, B. thuringiensis was isolated from faeces of cows and goats. The phenotypic characterization revealed that the B. thuringiensis isolates are motile and harbour bipyramidal and spherical crystals, which was confirmed by the electron microscopic studies. The biochemical characterization confirmed the haemolytic nature and nitrate reduction ability of the B. thuringiensis isolates. There is a distinct variation in protein profiles among the isolates as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. From this study we hypothesize that application of cattle manure in addition to maintaining the soil health also help augment B. thuringiensis population in soil, as a natural biocontrol agent and may play a role in the biological nitrogen cycle.
Key words: Bacillus thuringiensis, isolation, animal faces.