An azotobacter is a bacterium in the genus Azotobacter, which includes at least six known species. These bacteria are found in soils all over the world, and they are free-living, living independently rather than forming symbiotic relationships with plants or other organisms. A sample of healthy soil should include a good selection of azotobacter bacteria, which can be clearly seen under the microscope and used as one criterion when evaluating soil health.
These bacteria are notable nitrogen fixers, converting free nitrogen into a form which can be used by plants. Their free-living lifestyle is somewhat unusual when compared with most other nitrogen fixing bacteria, which is one reason they are a topic of interest for scientists. Azotobacter species also have a number of potential industrial applications, with their nitrogen fixing habits being harnessed in the production of various commercial products.
Azotobacter bacteria are motile and rod-shaped. They are non-pathogenic, not causing diseases in humans and other organisms, and many species famously produce a thick slime. These bacteria are also notable for the production of large cysts which are designed to protect the bacteria when they are in a resting state. Azotobacter cysts can be clearly seen under magnification, and can be carefully sectioned to reveal the internal structures of the cyst. The cyst will not protect the bacteria from extremely harsh weather such as very high or low temperatures, but it does provide some protection, allowing the bacteria to go dormant periodically.
Some examples of Azotobacter species include A. chrococcum and A. vinelandii. Several species have been studied extensively in the lab environment to learn more about how they fix nitrogen and produce other substances of value to plants, and to discover more about the lifecycle of these bacteria and their tolerances for various environmental conditions. These bacteria can be cultured by researchers who want to develop a stock to work with, and by companies which utilize them in the production of various products.
The soil is usually teeming with bacteria, and a small soil sample can contain an astounding array of organisms. Soil health involves a very delicate balance of bacteria and organic material in the soil, and it can be easily disturbed by poor soil management practices or harsh environmental conditions. Researchers are very interested in learning more about all of the organisms involved in soil health, and determining how and why soil becomes unbalanced and unhealthy so that poor soil can be remediated.