The following bacteria are important in the nitrogen cycle except?

Rhizobium is not directly involved in the nitrogen cycle. The nitrogen cycle is the process by which nitrogen is converted between different forms in the environment, such as from atmospheric nitrogen gas (N2) to ammonium (NH4+) and nitrate (NO3-) ions that plants can use for growth. This cycle involves a variety of microorganisms that play different roles in the process. Bacillus, Nitrobacter, and Nitrosomonas are all involved in the nitrogen cycle. Nitrosomonas converts ammonium to nitrite, and Nitrobacter converts nitrite to nitrate. Bacillus, on the other hand, plays a role in the decomposition of organic matter and the release of ammonium into the soil. Rhizobium is a soil bacteria that forms a symbiotic relationship with legume plants, helping them to convert atmospheric nitrogen into a form that the plant can use. While this process indirectly contributes to the nitrogen cycle, it is not directly involved in the conversion of nitrogen between different forms in the environment.