A biofertilizer is a substance which contains living microorganisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promotes growth by increasing the availability of primary nutrients to the host plant.
Azotobacter are free living bacteria that can fix atmospheric nitrogen into the soil, being a great source to obtain a natural bio fertilizer that can be used in the cultivation of most crops. Azotobacter has the ability to fix atmospheric nitrogen by the conversion to ammonia. Plants are able to utilize the ammonia as a nutrient. Azotobacter can accomplish nitrogen fixation by using three different enzymes which are termed as Nitrogenases. The enhanced versatility of Azotobacter bacteria makes the microbe attractive for agricultural purposes.