Question

Which of the following is/are the example of nitrifying bacteria?

• A. Nitrosomonas
• B. Nitrobacter
• C. Nitrospira
• D. Nitrosomonas, Nitrobacter, Nitrospira

Hint:

Nitrifying bacteria convert ammonia $\rightarrow$ nitrite $\rightarrow$ nitrate in soil nitrogen cycle.

Answer 1

The Correct Option is D

Step 1: Nitrification happens in two steps, ammonia to nitrite, then nitrite to nitrate.
Step 2: Nitrosomonas oxidises ammonia to nitrite (step 1).
Step 3: Nitrobacter and Nitrospira both oxidise nitrite to nitrate (step 2).
Step 4: Since all three organisms take part in nitrification, the correct answer is Nitrosomonas, Nitrobacter, Nitrospira.