Bacillus are rod-shaped, gram-positive bacteria that can form endospores allowing them to survive in extreme environments. They are found ubiquitously in soil, water and air. Some Bacillus species are pathogenic to humans and animals, causing diseases like anthrax and food poisoning, while others have uses like the insect pathogen B. thuringiensis. Bacillus exhibit a variety of metabolic capabilities including degrading plant and animal substrates, producing antibiotics, and fixing nitrogen. They reproduce through binary fission and form endospores during stressful conditions which has allowed the genus to thrive in diverse habitats.

1. General characteristics
 Rod shape
 Gram positive; some
species cultures turn
Gram-negative with age
 Obligate aerobes but
some are facultative
anaerobes
 Test positive for catalase
test
 Produce endospores
under stressful condition
 Free living non-
pathogenic and
pathogenic Bacillus
· Habitat
• Ubiquitous: found in soil, water, air and in
extremes environments of high PH and
temperature
 Bacillus acidophilus – acidic environment
 Bacillus thermophiles –high temp.
Isolation:
• Heat soil sample in water upto 800c and plate on
specific media
Distribution: Ubiquitous
Hosts:
Animal host; Man (Bacillus anthracis), Insects
(Bacillus thuringiensis).
Plant hosts: WBW, B. megaterium, B. circulans in
date palm tissue culture, B. polymyxa in tomato
seedling blight.
Life style
 Bacillus can degrade substrates from both plants and animals
including cellulose, starch, pectin, proteins, and hydrocarbons.
 Antibiotics producers
 Heterotrophic nitrifiers, denitrifiers and nitrogen fixers
 Are iron precipitators; selenium oxidixers
 Oxidize and reduce manganese
 Chemolithotrophs
 Acidophiles, alkalophiles, psychrophiles and thermophiles
Cause food poisoning and food spoilage
Some important Bacillus
 Bacillus anthracis; causes anthrax in human
 Bacillus cereus: causes food poisoning
 Bacillus thuringiensis: (carry Bt toxin) insect pathogen
 Bacillus subtilis: important research model organism both in cell
and molecular biology
History
 The first described Bacillus was named Vibrio
subtilis in 1835 by Christian Gottfried
Ehrenberg
 In 1872, Ferdinand Cohn renamed the organism
as Bacillus subtilis after its ability to produce
endospores which are round, oval or cylindrical
 Cohn and Koch made the early discoveries about
spores resistant to heat and the development
cycle of sporeformers, working with B. subtilis
and anthracis respectively.
BACILLUS SPECIES: AEROBIC ENDOSPORE FORMING GRAM POSITIVE BACTERIA BY RUFUS AKINRINLOLA GRAD STUDENT ,UNL
Reproduction
Asexual reproduction; binary
fission; mitosis
Classification and Phylogeny
Classification methods
 Physiological classification
 DNA bases (G+C content) and DNA-DNA hybridization
 16s rRNA
Reference
Slepecky, R. A., & Hemphill, H. E. (2006). The genus
Bacillus—nonmedical. InThe prokaryotes (pp. 530-
562). Springer US.