Q. Which is a free living nitrogen fixing bacterium?
- Pseudomonas
- Azotobacter
- Nitrosomonas
- Rhizobium
Solution :
Correct option : B Reduction of inert atmospheric nitrogen to ammonia by living organisms is called biological nitrogen-fixation. Only certain prokaryotic organisms (some bacteria and cyanobacteria) are capable of fixing N2. Such microbes are called N2-fixers. These N2-fixing microbes contain an exclusive enzyme, Nitrogenase that is capable of reducing nitrogen. Azotobacter is the free-living N2-fixing bacteria. It is aerobic i.e., it requires oxygen for respiration.
