The genus Bacillus is a phenotypically large, diverse
collection of Gram-positive or Gram-variable, endospore-forming,
aerobic, facultative anaerobic, and
rod-shaped bacteria that have undergone considerable
reclassification along with the advances in molecular
biology with a high phylogenetic heterogeneity (Claus and Berkely 1986; Nazina et al. 2001). The genus
Bacillus and related genera are distributed widely in
nature and include thermophilic, psychrophilic,
acidophilic, alkalophilic, and halophilic bacteria that
utilize a wide range of carbon sources for heterotrophic
growth or are the autotrophs. The habitat of
Brevibacillus overlaps with Bacillus and they are
found in diverse environments including rocks, dust,
aquatic environments, and guts of various insects and
animals (Nicholson 2002).