Rhizobium is a type of bacteria that lives in the soil and forms a symbiotic relationship with certain plants, including leguminous plants such as peas, beans, and clover. It attaches to the roots of these plants and produces nodules, where it fixes atmospheric nitrogen and converts it into ammonia that can be used by the plant for its growth and development. Rhizobium is a diazotrophic bacteria that fix atmospheric nitrogen. The bacteria are rod-like and belong to the Bacillus group, and they have different cell organelles such as nucleoid (DNA), ribosomes, mesosome, cytoplasm, and capsule. Rhizobium bacteria structure differs from other spherical or spiral bacteria, and it comprises two cell membranes in its cell wall. Rhizobium belongs to Alphaproteobacteria Class, Rhizobiales Order, and Rhizobiacea family. Rhizobium is not a disease-causing bacteria.