The microorganisms help in increasing the fertility of the soil. Certain microbes like bacteria are very good decomposers. They decompose the dead organic matter. This when mixed with the soil makes it fertile. Microorganisms have the ability to fix atmospheric nitrogen, solubilize and mobilize phosphorus, produce antibiotics and disease suppressing molecules. Owing to these properties, they are used in agriculture as biofertilizers and biopesticides. They are also important in the treatment of solid waste and sewage. These microbes play a crucial role in the fermentation process to obtain a number of products. The two common products obtained by fermentation process through industrial processes are fermented beverages, malted cereals, broths, fruit juices, antibiotics, etc. Bacteria decompose dead organic matter and releases simple compounds in the soil, which can be taken up by plants. Nitrogen-fixing bacteria fix atmospheric nitrogen and increase the nitrogen content of the soil, which can be readily absorbed by plants.