Environmental and Industrial Use of Bacillus Subtilis

Present in the environment in the air, soil and water, Bacillus subtilis is a bacterium that is generally harmless to humans. It does, however, have an enviable ability to produce enzymes that mankind has harnessed for industry. The species can also break down various naturally-occurring pollutants, which is useful for environmental purposes, and has additional uses as a pesticide. The value of microbes like B. subtilis to industry is that cultivating them on a large scale to produce enzymes and other substances tends to be cheap and relatively uncomplicated.

Some industries use Bacillus subtilis to produce enzymes that are useful in the cleaning industry. For example, the species can produce proteases, which are enzymes that break down protein. These proteases are an ingredient in some washing detergents and can also be used in the leather industry to break down unwanted substances on skins.

Amylases, which break down starch, are some other useful enzymes that B. subtilis can produce in bulk. Starch breakdown is a useful step in the production of paper and in the treatment of textiles.

The practice of using species like B. subtilis to break down pollutants is called bioremediation. The bacterium can actually eat up light fractions of crude oil like paraffin and convert them into less environmentally harmful substances. B. subtilis can also produce a surfactant, which helps to disperse crude oil, and the enzymes that it can produce include lipases, which can be turned into bioremediants for fat-rich pollutants like sewage and other waste water.

Certain bacterial species can interfere with the ability of pathogens to attack crops. A strain of B. subtilis called QST 713 is able to trigger a strong resistance to attack by fungi in crops that have been treated with it. The bacterium can also combat the potentially infectious fungi by various mechanisms, such as direct competition for nutrients.

As Bacillus subtilis produces a lot of enzymes that are valuable in fermentation, the species is in demand for certain food processing industries. An additional point in B. subtilis's favor is that the bacterium is classed by the U.S. Food and Drug Administration as "Generally Regarded as Safe" or "GRAS," which means it is regarded as safe for consumers to eat. An example of a Bacillus subtilis-fermented food is natto, a soybean product popular in Japan.