Question

Microorganisms that oxidise ammonia to nitrite
(A) Nitrosomonas
(B) Thiobacillus
(C) Nitrobacter
(D) Nitrosolobus
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A) and (D) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

Nitrosomonas and Nitrosolobus convert ammonia to nitrite in nitrification.

Answer 1

The Correct Option is B

Step 1: Nitrification has two stages carried out by different bacterial groups.
Step 2: Ammonia to nitrite oxidation is done by Nitrosomonas and Nitrosolobus.
Step 3: Nitrobacter acts later, oxidising nitrite to nitrate, and Thiobacillus oxidises sulphur, not nitrogen.
Step 4: Correct answer is (A) and (D) only.