Question

In the process of nitrification, ammonia is first oxidized to nitrite by

• A. Nitrosomonas and Nitrosococcus
• B. Nitrosomonas and Nitrobacter
• C. Pseudomonas and Nitrosococcus
• D. Pseudomonas and Thiobacillus

Answer 1

The correct option is A Nitrosomonas and Nitrosococcus

First step, ammonium ions are oxidised to nitrites. Nitrosomonas are the most important agents of oxidation of ammonia to nitrite in soil. Certain other bacteria are Nitrosococcus , Nitrosolobus ,etc.

Second step , oxidation of nitrite to nitrate takes place by Nitrobacter.

So the correct option is "Nitrosomonas and Nitrococcus".