Difference Between Bacillus Subtilis and Bacillus Cereus

The key difference between Bacillus subtilis and Bacillus cereus is that Bacillus subtilis is fermenting mannitol, but it lacks the ability to produce enzyme lecithinase while Bacillus cereus is not fermenting mannitol, but it produces enzyme lecithinase.

Bacillus is a genus of gram-positive, rod-shaped bacteria. They are members of phylum Firmicutes. There are 266 named species. Bacillus species can either be oxygen-dependent obligate aerobes or facultative anaerobes. Bacillus species produce endospores. These species can reduce themselves to oval endospores and can remain dormant for years. The endospores are resistant to heat, radiation, desiccation, and disinfectants. Bacillus subtilis and Bacillus cereus are two types of species of this genus Bacillus.

CONTENTS

1. Overview and Key Difference
2. What is Bacillus Subtilis 
3. What is Bacillus Cereus
4. Similarities – Bacillus Subtilis and Bacillus Cereus
5. Bacillus Subtilis vs Bacillus Cereus in Tabular Form
6. Summary – Bacillus Subtilis vs Bacillus Cereus

What is Bacillus Subtilis?

Bacillus subtilis is a gram-positive, rod-shaped, mannitol-fermenting bacterium that lacks the ability to produce enzyme lecithinase. It is also catalase positive. This bacterium is commonly found in the soil and gastrointestinal tract of ruminants and humans. This bacterium produces a tough and protective endospore. This allows it to tolerate harsh environmental conditions. B. subtilis has been classified as an obligate aerobe historically though evidence exists to prove it is a facultative anaerobe. It is one of the best bacteria that can be used in secreted enzyme production. Therefore, it is involved in industrial scale biotechnological productions. Moreover, this bacterium is a highly popular modal organism. It produces white colonies in nutrient agar.

B. subtilis can divide symmetrically through binary fission to make two daughter cells. The endospore of this bacterium can remain viable for decades and is resistant to unfavourable conditions such as drought, salinity, extreme pH, radiation, and solvents. Scientists have studied the replication of a single circular chromosome of this bacterium as a model organism and have found that the replication of B. subtilis proceeds bidirectionally, and replication terminates due to a sequence in the terminus region of DNA (Ter site) of this bacterium. Furthermore, B. subtilis genome has about 4,100 genes. Natural bacterial transformation process also can be observed in these bacteria. In alternative medicine, this bacterium is used to simulate a broad-spectrum immune activity. It activates the secretion of specific antibodies such as IgM, IgG and IgA and induces interferon IFN-α/IFNγ that shows cytotoxicity towards tumours. The antibiotic bacitracin was also first isolated from B. subtilis. Other than that, it is widely used for enzyme production, such as amylase and protease. It is also used as probiotics and soil inoculants, and bio fungicides in agriculture.

What is Bacillus Cereus?

Bacillus cereus is a gram-positive, rod-shaped mannitol non-fermenting bacterium that produces the lecithinase enzyme. It is also a facultatively anaerobic, motile, beta haemolytic spore-forming bacterium. It is commonly found in soil and food. Some strains of them are highly pathogenic and cause foodborne illness in humans. The virulent factors of this bacterium include cereolysin and phospholipase C. Some strains are beneficial as probiotics.

A population of Bacillus cereus can double their number at 30 °C within 20 minutes depending on food products. B. cereus produces off white colonies in nutrient agar. The genome size of B. cereus is around 5-7.9, with approximately 5397 genes. Furthermore, this bacterium also has a circular chromosome.

What are the Similarities Between Bacillus Subtilis and Bacillus Cereus?

• Bacillus subtilis and Bacillus cereus are two bacteria belonging to the genus Bacillus.
• Both are gram-positive and rod-shaped.
• They are motile.
• They possess flagella.
• Both are beta-haemolytic bacteria.
• They form endospores.
• Both are useful as probiotics.

What is the Difference Between Bacillus Subtilis and Bacillus Cereus?

Bacillus subtilis is fermenting mannitol, but it lacks the ability to produce enzyme lecithinase. On the other hand, Bacillus cereus is not fermenting mannitol, but it produces the enzyme lecithinase. So, this is the key difference between Bacillus subtilis and Bacillus cereus. Furthermore, Bacillus subtilis is non-pathogenic to humans. But Bacillus cereus is pathogenic to humans. Thus, this is another significant difference between Bacillus subtilis and Bacillus cereus.

The below infographic compiles the differences between Bacillus subtilis and Bacillus cereus in tabular form.

Summary – Bacillus Subtilis vs Bacillus Cereus

Bacillus is a genus of gram-positive and rod-shaped bacteria. Bacillus subtilis and Bacillus cereus are two types of bacterial species belonging to the genus Bacillus. Bacillus subtilis is a non-pathogenic bacterium that ferments mannitol, but it lacks the ability to produce enzyme lecithinase. In contrast, Bacillus cereus is a pathogenic bacterium that does not ferment mannitol but produces enzyme lecithinase. Thus, this is the summary of the difference between Bacillus subtilis and Bacillus cereus.

Reference:

1.“Bacillus Subtilis.” An Overview | ScienceDirect Topics.
2. Bottone, Edward J. “Bacillus Cereus, a Volatile Human Pathogen.” Clinical Microbiology Reviews, American Society for Microbiology (ASM).

Image Courtesy:

1. “Bacillus subtilis by togopic” By Database Center for Life Science (DBCLS) (CC BY 3.0) via Commons Wikimedia
2. “Bacillus cereus SEM-cr” By Mogana Das Murtey and Patchamuthu Ramasamy – [1] (CC BY-SA 3.0) via Commons Wikimedia