Question

Explain how Nitrification is different from Nitrogen fixation. Mention the role of Thiobacllus in nitrogen cycle? What do you understand by biological Nitrogen fixation?

Answer 1

• Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia or related nitrogenous compounds.
• Thiobacillus helps in the conversion of nitrates in the soil to free atmospheric nitrogen, thus depleting soil fertility and reducing agricultural productivity.
• Biological nitrogen fixation is the process whereby atmospheric nitrogen (N=N) is reduced to ammonia in the presence of nitrogenase. Nitrogenase is a biological catalyst found naturally only in certain microorganisms such as the symbiotic Rhizobium and Frankia, or the free-living Azospirillum and Azotobacter.