It is common to think of bacteria as causing various diseases . However, many of them are of great importance to man, to the planet and to living things in general.
Most bacteria are heterotrophic , that is, they feed on the organic material produced by other living things.
Thus, most of them get their food from dead organisms, from their debris or feces. In this process, the organic substances found in the body of dead animals and plants are transformed into simple inorganic substances ( minerals and certain gases), which will be used by other living things, especially chlorophylls.
That is why bacteria and also fungi are called decomposing beings, because they act by promoting the recycling of matter . If it were not for these agents, corpses, leaves, logs, and feces would accumulate in soil and water.
Another excellent example of how bacteria contribute to soil fertility is what occurs in the nitrogen cycle .
The Nitrogen makes up approximately 78% of the atmosphere. It is a very important substance for the formation of proteins and the genetic material of living things. However, animals and plants can not absorb it directly from the air.
Some autotrophic bacteria that live in the soil can capture this gas and, with other elements, are able to produce nitrogenous salts in the form of ammonia, which can be absorbed by some plants. Similar work is done by other bacteria associated with root nodules of legumes, such as beans, peas, peanuts, etc.
The process of capturing and transforming atmospheric nitrogen into ammonia carried by these bacteria is called fixed tio the biological O gene .
Thus, only a few plants absorb nitrogen salts directly in the form of ammonia. Most plants absorb nitrogenous salts in the form of nitrate. For nitrate formation, two other groups of bacteria act. One group of bacteria transforms the ammonia into nitrite, while the other transforms nitrite into nitrate, which is absorbed by the roots of most plants.
- Fixing bacteria transform atmospheric nitrogen into ammonia;
- The decomposition of animals and plants forms ammonia;
- Bacteria transform ammonia into nitrite;
- Bacteria transform nitrite into nitrate, which is absorbed by plants;
- Bacteria transform nitrate into atmospheric nitrogen.
Some bacteria live on a mutualistic association in the intestine of ruminant herbivores , such as cattle, goats and sheep, where they obtain shelter and food and in exchange produce substances that digest the cellulose, which is absorbed by the intestines of these animals. In the human gut, there are also bacteria of great importance composing the intestinal flora; they contribute to the absorption of substances by the body.
Bacteria of the genus Lactobacilli and Streptococcus are useful in the dairy industry. They help in ferments tio the – biological process of obtaining energy held by some milk microorganisms, which allows the production of cheeses, curds, yogurts and other derivatives.
We can also produce vinegar by means of the oxidation of wine. This is what bacteria of the genus Acetobacter do .
Currently, bacteria are useful in the pharmaceutical industries. Through biotechnology , various drugs are produced with the use of bacteria, such as vitamins , antibiotics, growth hormone and insulin, the latter two identical to those produced by the human body.