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Bacillus Bacteria

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Meaning of Bacillus Bacteria

IVSAT 2024

Gram-positive rod-shaped bacteria known as Bacillus (Latin for "stick") belong to the phylum Firmicutes and have 266 recognised species. The plural Bacilli is the name of the class of bacteria to which this genus belongs, and the term is also used to describe the form (rod) of specific bacteria.

One of the largest species of Bacillus is B. megaterium, which is approx 1.5 μm (micrometres; 1 μm = 10−6 m) across 4 μm long. These bacteria majorly occur in chains. Ferdinand Cohn in 1877 provided a full description of two different forms of hat bacillus. One is that it could be killed when kept in exposure to heat and another shows resistivity towards heat. 

Bacillus can be reduced to oval endospores and remain dormant for years in this state.

Bacillus is a genus of bacteria that comprises both free-living (nonparasitic) and parasitic harmful species.

Endospores are resistant to heat, chemicals, sunlight and they are widely distributed in nature, majorly in soil, from which they invade dust particles. 

Classification, Nature of Cell Wall, Uses, Importance, and Diseases: Bacillus Bacteria


Domain: Bacteria

All of the members are prokaryotic. They have peptidoglycan in their cell walls. Peptidoglycan is made up of amino acids and sugars. It also aids in the formation of the cell wall. The majority of prokaryotes are unicellular. They have no membrane-bound nucleus, mitochondria, or chloroplast.

Kingdom: Eubacteria

This kingdom's members are all single-celled and prokaryotic. The solitary kingdom of bacteria is Eubacteria.

Phylum: Firmicutes

Firmicutes are gram-positive with a low DNA percentage.

Class: Bacilli

The morphological shape of the organisms is implied in the name of this class.

Order: Bacillales

The members can form endospores.

Family: Bacillacae

Bacillacae members are all Aerobic and use oxygen in cellular respiration.

Genus: Bacillus

Bacillus species live in soil, can be found in water, and have peritrichous flagella that help them move.

Species: Bacillus cereus

Bacillus cereus is differentiated from its counterparts. Bacillus anthracis and Bacillus thuringiensis are distinguished by phenotypic and pathogenic consequences.

Bacillus are Further classified into Different Types based on Rod-Shape Cells

Bacillus: Single unattached cell, that looks like a rod. Examples are Bacillus cereus, Salmonella enterica, etc.

Diplobacilli: In these bacteria, two rods are attached and found in pairs after cell division. Examples are Moraxella Bovis, Klebsiella rhinoscleromatis, etc.

Streptobacilli: In them, bacilli are arranged in a single chain due to cell division in a single plane. Examples are Streptobacillus moniliformis, Streptobacillus felis, etc.

Coccobacilli: They are of oval shape and short in comparison to other bacteria. Examples: Chlamydia trachomatis, Haemophilus influenzae, Gardnerella vaginalis, etc.

Palisades: In these bacteria, cells bends after cell division and they arranged themself in a palisade.Example: Corynebacterium diphtheriae

Nature of Cell Wall

  • The structure which is found outside the cell, which forms a second barrier between the bacterium and the environment is called cell structure. 

  • The cell wall also maintains the rod shape and withstands the pressure generated by the cell's turgor. 

  • Its cell structure is made up of an inner membrane and thick peptidoglycan.  Peptidoglycan keeps the cell in shape.

  • The polysaccharide part of the cell wall accounts for half of the cell wall.

  • It's a neutral polysaccharide made up of N-acetylglucosamine, N-acetylmannosamine (ManNac), N-acetylgalactosamine, and glucose in a 4: 1: 1: 1 molar ratio.

  • A repeating tetrasaccharide molecule is indicative of the acidic section of the cell wall.

  • Techoic acids, which are composed of N-acetylglucosamine, galactose, glycerol, and phosphorus in a molar ratio of 1: 1.4: 1: 1, make up 5% of the cell wall.

  • Some B. cereus strains have unique peptidoglycan with only a few oligomers.

  • Muropeptides that have been cross-linked are dimmers, and many of them lack the N-acetyl group.

In pathogenic strains, these differentiating traits impact cell surface charge, which contributes to the attachment of an outer capsule or an S-layer.

The very first bacteria for which the role of actin as cytoskeleton in cell shape determination and peptidoglycan synthesis was identified in Bacillus subtilis. One of the major roles of the cytoskeleton is to maintain the shape of bacteria. 

Importance and Uses

  1. Bacillus spp. are widespread in a wide range of environments, including soil, and are resistant to harsh environmental conditions. These Bacillus bacteria have the capability to survive in extreme conditions like  high pH (B. alcalophilus), high temperature (B. thermophilus), and high salt concentrations, because of this nature they are ubiquitous in nature. 

  2. The majority of Bacillus species, as well as their products, are deemed safe for use in the environment.

  3. Because of their potential to release many bioactive compounds, these bacteria are recommended for commercialization.

  4. They keep their viability and are simple to store.

  5. Bacillus-based commercial preparations are created and distributed all over the world.

  6. Bacillus coagulans can also make foods that are very acidic, like tomato-based foods, taste bad.

  7. One of species of Bacillus bacteria i.e. Bacillus thuringiensis has the ability to produce toxins that can kill insects and thus they are insecticides in nature. 

  8. Bacteria B. siamensis can inhibit plant pathogens from entering as they have antimicrobial compounds in them. 

  9. Few species of Bacillus act as naturally competent for DNA uptake by transformation. 


Some of the common diseases caused by Bacillus bacteria are:

  • Infections caused by Bacillus subtilis are endocarditis, pneumonia, and septicemia. This problem mainly occurs in patients who have an immune disorder. 

  • Bacillus anthracis, as it causes skin, lungs, and bowel infections and these diseases are deadly to the human body. 

  • Bacillus cereus causes food spoilage which can cause food poisoning. 

About Bacillus

  • Gram-positive Bacilli form bacteria are Actinomyces, Clostridium, Bacillus or gram-negative bacteria, e.g. Escherichia, Klebsiella, Salmonella, Streptobacillus, etc. 

  • They have the capability of serving at high temperatures i.e. at 4200 C. 

  • They are mostly non-parasitic and free-living in nature. 

  • They are known to be one of the most abundantly found bacteria. 

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FAQs on Bacillus Bacteria

1. Where are the species of Bacillus Bacteria used?

Many Bacillus species can produce large numbers of enzymes, which are employed in a variety of sectors. For example, alpha-amylase is used in starch hydrolysis, and protease subtilisin is used in detergents.

Surfactants and mycosubtilins are two lipopeptides that Bacillus species can make and produce. Bacillus species can also be found in sponges from the sea. Bacillus subtilis (strains WS1A and YBS29) found in marine sponges can produce a variety of antibacterial peptides. In Labeo rohita, these Bacillus subtilis strains can cause disease resistance.

2. What are the most important species of Bacillus to be noted?

There are a few Bacillus species worth noting include:

  • Anthrax is caused by Bacillus anthracis.

  • Bacillus subtilis is regarded as a model bacterium. It is frequently utilised in the field of genetic engineering.

  • Bacillus cereus is a bacteria that causes food poisoning.

  • Bacillus thuringiensis is a pest-control bacteria. It secretes a poison that can harm certain moths and butterflies.

These bacteria produce endospores when they are stressed. These are not real spores, although they, like survival pods, can remain dormant for lengthy periods.

3. Is Bacillus Coagulans a good bacteria?

Bacillus coagulans is a probiotic, or beneficial bacteria. Lactic acid is produced by it, although it is not the same as Lactobacillus, a separate type of probiotic.

During its reproductive life cycle, B. coagulans can produce spores. This is in contrast to Lactobacillus and other probiotics. This feature permits B. coagulans to go dormant in hostile environments, which would otherwise kill other probiotics.

As a result, this bacteria strain is exceptionally hardy. It can withstand tough stomach conditions like high acidity. This could explain why B. coagulans are so helpful in treating stomach problems and other diseases.

4. Does bacteria grow in refrigerators?

Pathogenic bacteria, which cause foodborne illness, and spoilage bacteria, which cause foods to decay and produce disagreeable scents, tastes, and textures, belong to two separate groups of bacteria. 

Pathogenic bacteria can proliferate quickly in the "Danger Zone," which is defined as the temperature range between 40 and 140 degrees Fahrenheit. A pathogen's presence cannot be detected because it does not affect the flavour, smell, or appearance of the meal. 

Spoilage bacteria can thrive in cold environments, such as the refrigerator. They eventually cause food to develop foul flavours and odours.

5. Where do Bacillus Bacteria live and can they live in an extreme environment?

The great majority of these bacteria are environmental organisms that can be found in soil, air, dust, and garbage. These organisms are ubiquitous components of the microflora in cleanrooms and often dominate indoor air in occupied buildings. They are also numerous in dust and on surfaces.

Bacillus is an example of a microorganism that can endure a wide pH range as well as high temperatures. When metagenomic techniques and 16S DNA sequencing were discovered, the astonishing variety of microbial life in harsh settings became apparent.

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