Question

Which of the following is not related to ${{\text{N}}_{\text{2}}}$ fixation?
A) Rhizobium
B) Anabaena
C) Pseudomonas
D) Azotobacter

Answer 1

Nitrogen fixation is a chemical process in which molecular nitrogen ( ${{\text{N}}_{\text{2}}}$ ) in the air is transformed into ammonia ( $\text{N}{{\text{H}}_{\text{3}}}$ ) or similar nitrogenous compounds, most often in soil or aquatic environments, but sometimes in industry. Except for a few bacteria, atmospheric nitrogen is molecular dinitrogen, a generally non reactive molecule that is biologically worthless. Biological nitrogen fixation, also known as diazotrophs, is a microbially driven process that uses the nitrogenase protein complex to convert dinitrogen ( ${{\text{N}}_{\text{2}}}$ ) gas to ammonia ( $\text{N}{{\text{H}}_{\text{3}}}$ ).

Complete Step By Step Answer:
Because all nitrogen-containing organic molecules, including as amino acids and proteins, nucleoside triphosphates, and nucleic acids, require the production of fixed inorganic nitrogen compounds, nitrogen fixation is fundamental to life. It is necessary for agriculture and fertiliser production as part of the nitrogen cycle. It also has an indirect impact on the production of all nitrogen chemical compounds, including certain explosives, medicines, and colours.
Nitrogen fixation is essential to life since all nitrogen-containing organic molecules, including as amino acids and proteins, nucleoside triphosphates, and nucleic acids, need the synthesis of fixed inorganic nitrogen compounds. As part of the nitrogen cycle, it is required for agriculture and fertiliser production. It also has an indirect effect on the manufacture of all nitrogen chemical compounds, such as explosives, medications, and colours.
Free-living and symbiotic bacteria are two types of nitrogen-fixing bacteria. Rhizobia are symbiotic soil bacteria that fix nitrogen (diazotrophs) once they've established themselves inside legume root nodules.
Anabaena is a symbiotic cyanobacterium capable of nitrogen fixation, which allows it to use atmospheric nitrogen ( ${{\text{N}}_{\text{2}}}$ ). Azotobacter species are nitrogen-fixing bacteria that live on their own and do not require symbiotic relationships with plants to fix molecular nitrogen from the atmosphere. However, Saccharomyces is a fungus that is not connected to nitrogen fixation but is involved in the fermentation process.
Hence option B is correct.

Note:
Desfosses recognised the potential of atmospheric nitrogen reacting with specific compounds for the first time in 1828. At high temperatures, he discovered that combinations of alkali metal oxides and carbon react with nitrogen. In the 1860s, Margueritte and Sourdeval created the first industrial method, which used barium carbonate as a starting material. When barium cyanide interacts with steam, ammonia is produced. Henry Cavendish initially suggested a method for nitrogen fixation in 1784, utilising electric arcs to react nitrogen and oxygen in the air. In the Birkeland–Eyde procedure, this approach was used.