Azotobacter is bacteria specially used as biofertilizer in soil. Azotobacter bring atmospheric nitrogen to soil when applied to the soil. These bacteria utilize atmospheric nitrogen gas for their cell protein synthesis. This cell protein is then mineralized in soil after the death of Azotobacter cells thereby contributing towards the nitrogen availability of the crop plants. Azotobacter spp. is sensitive to acidic pH, high salts, and temperature.
PGPB are plant growth-promoting bacteria, commonly known as any bacterial responsible for the nutrient transfer to the plants. The role and importance of bio-fertilizers in sustainable crop production have been studied well.
Biofertilizers play a very significant role in improving soil fertility by fixing atmospheric nitrogen, both, in association with plant roots and without it, solubilise insoluble soil phosphates and produces plant growth substances in the soil.
Biofertilizers are biological products containing living microorganisms that, when applied to seed, plant surfaces, or soil, promote growth by several mechanisms such as increasing the supply of nutrients, increasing root biomass or root area and increasing nutrient uptake capacity of the plant. The concept of biofertilizers has changed along with the state of knowledge about associations occurring between soil microorganisms and plants.