Mineral Nutrition Question 34
34. Which of the following bacteria reduce nitrate in soil into nitrogen?
(a) Nitrosomonas
(b) Nitrobacter
(c) Nitrococcus
(d) Thiobacillus
Show Answer
Answer : d
Hints & Solution
(d) Thiobacillus denitrificans, a type of denitrifiers, converts nitrates in soil to free atmospheric nitrogen, thus depleting soil fertility and reducing agricultural productivity. $ \begin{gathered} \text{ Nitrates (soil) } \xrightarrow[\text{ Denitrification }]{\downarrow} \text{ Nitrogen } \\ \text{ Pseudomonas denitrificans & } \\ \text{ Thiobacillus denitrificans } \end{gathered} $ Thiobacillus is a genus of Gram-negative Betaproteobacteria. Thiobacillus oxidizes thiosulfate and elemental sulphur to sulphate, and $A$. ferrooxidans oxidizes ferrous ions to the ferric form. This diverse oxidizing ability allows A. ferrooxidans to tolerate high concentrations of many different ions, including iron, copper, cobalt, nickel, and zinc.
