Microorganisms can help meet human energy needs in any of a number of ways. In their most obvious role in energy conversion, microorganisms can generate fuels, including ethanol, hydrogen, methane, lipids, and butanol, which can be burned to produce energy. Microorganisms play an important role in the acquisition and transfer of nutrients in soil. In particular, microorganisms can solubilise and mineralize P from inorganic and organic pools of total soil P. Microorganisms increase the source of nitrogen in the soil, or they can supply it directly to the plant, as they have the ability to take and set nitrogen from the atmosphere. Thanks to microorganisms, there is an increase in the bioavailability of phosphorus in the soil. Microorganisms play an important role in the nutrient cycle. Some bacteria secrete phytochemicals and organic acids that are helpful in the growth and development of plants. Microorganisms help maintain soil pH but balance nutrients and minerals. Soil microorganisms are responsible for most of the nutrient release from organic matter. When microorganisms decompose organic matter, they use the carbon and nutrients in the organic matter for their own growth. They release excess nutrients into the soil where they can be taken up by plants.

Soil microorganisms decompose these materials into inorganic nutrients and humus and are termed as mineralization and humification, respectively. The released nutrients further get chelated as organo-metal-complexes or leached through the soil or immobilized or become available to the plants. The main effects of the presence of microorganisms in the soil are: Improved plant nutrition. Microorganisms increase the source of nitrogen in the soil, or they can supply it directly to the plant, as they have the ability to take and set nitrogen from the atmosphere. Microbes create nutrient-like carbon, nitrogen, oxygen, hydrogen, phosphorus, potassium, trace elements, vitamins and amino acids and make them available for plant in right form for their growth and health. The cycling of nutrients such as carbon, nitrogen, and sulfur is completed by their ceaseless labor. Organic carbon, in the form of dead and rotting organisms, would quickly deplete the carbon dioxide in the atmosphere if not for the activity of decomposers. Bacteria and fungi are the major decomposer on earth and crucial component for composting and humus formation. One of the most essential functions of bacteria is decomposition, which involves the dissolution of these species and the release of nutrients back into the atmosphere and another essential function of bacteria in nitrogen cycling. Heterotrophic bacteria, which include all pathogens, obtain energy from oxidation of organic compounds. Carbohydrates lipids and protein are the most commonly oxidized compounds. Biologic oxidation of these organic compounds by bacteria results in synthesis of ATP as the chemical energy source. The cycling of nutrients such as carbon, nitrogen, and sulfur is completed by their ceaseless labor. Organic carbon, in the form of dead and rotting organisms, would quickly deplete the carbon dioxide in the atmosphere if not for the activity of decomposers.