Question

Which of the following organisms helps in the process of changing nitrite to nitrate?

• A. Nitrobacter
• B. Nitrosomonas
• C. Pseudomonas denitrificans
• D. Thiobacillus denitrificans

Answer 1

The correct option is A Nitrobacter

Nitrogen fixation is the initial step of the nitrogen cycle. Here, atmospheric nitrogen ($N_2$) which is primarily available in an inert form, is converted into the usable form -ammonia ($N{H}_3$). Nitrification is the conversion of ammonia into nitrites and then into nitrates. This is done by the bacteria Nitrosomonas and Nitrobacter respectively.

Nitrates are reduced back into nitrogen in the soil by a process called denitrification. This process is performed by bacteria like Pseudomonas denitrificans, etc.