Bacillus lichenformis
Erin Pringle

Bacillus licheniformis is an interesting type of bacteria because it affects humans in many different ways. B. licheniformis is Gram-positive and rod-shaped. It is a motile bacterium, a facultative anaerobe (unlike other bacilli that are typically aerobic), and closely related to Bacillus subtilis. B. licheniformis produces endospores, and is usually found in the soil as spores. It is an apathogenic microorganism that is usually associated with plants and plant materials.

B. licheniformis has been approved as being used to treat ornamental plants to protect them from fungal pathogens. It demonstrates antifungal activity by producing an antibiotic that acts against fungi. It may also produce an anti-fungal enzyme. B. licheniformis is effective against many types of fungi, especially those that cause leafspot and blight diseases. Its use is not recommended on plants that may be used for food or feed because it may be associated with food poisoning in humans and reproductive failure in cattle, sheep, and pigs. Sources differ in saying whether or not B. licheniformis is actually toxigenic. It is a common spoilage organism of milk, packaged meats, and some canned goods. Food poisoning by B. licheniformis is characterized by diarrhea. Vomiting also occurs in around half of the cases. The species has also been isolated from a number of human infections. In order for infections to occur, it seems that there must be a preceding case of trauma or immunosupression that allows the bacteria to multiply. However, the possibility of infection by B. licheniformis is low.

B. licheniformis is an important commercial bacterium because it is used to produce enzymes, mainly alpha-amylases and proteases. The enzymes are manufactured in large quantities through fermentation. They are then used in many different ways. They are added to cleaning detergents to improve their effectiveness. They help break down organic stains that are otherwise hard to remove. Enzymes were first used to improve the effectiveness of laundry detergent in 1913 by Otto Rohm. Otto Rohm was the founder of the chemical company Rohm and Hass. The proteolytic enzyme he used was derived from milled animal pancreases. However, it was actually quite crude with many impurities and could actually stain textiles. Enzymes from B. licheniformis are advantageous because they work best in warm alkaline conditions, which prevail in washing liquids. They also do not lose their activity in an environment that includes many potentially inhibitory chemicals. The proteases produced by B. licheniformis are also used for dehairing and batting in the leather industry. The alpha-amylases produced are also used for the desizing of textiles and starch modification for sizing of paper.

B. licheniformis is also used to produce the polypeptide antibiotic bacitracin. Bacitracin is mainly active against Gram-positive bacteria. It is added to topical ointment to prevent minor cuts and abrasions from developing infections. It is added to eye ointment to treat minor bacterial infections of the eyelids.

While B. licheniformis is a relatively common bacterium, it is important to humans in many different ways. In the future we may find even more uses for its enzymes as well as better understand how much virulence it actually possesses.











*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.


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