Question

Which of the following statements about methanogens is not correct?

• A. They can be used to produce biogas
• B. They are found in the rumen of cattle and their excreta
• C. They grow aerobically and breakdown cellulose-rich food
• D. They produce methane gas

Answer 1

The correct option is C They grow aerobically and breakdown cellulose-rich food

Methanogens are categorised under archaebacteria which have the ability to produce methane along with carbon dioxide and hydrogen by breaking down cellulose-rich food. These are unicellular microorganisms and obligate anaerobes, i.e., they grow in absence of oxygen and are extremely sensitive to it. They are similar to prokaryotes as they do not possess cell organelles nor have a well defined nucleus in their cells. But their cellular walls have no peptidoglycan. One of the most common methanogen is Methanobacterium.

These are commonly found in the anaerobic sludge during
sewage treatment and rumen (part of stomach) in cattles. In rumen, these help in the breakdown of cellulose. Hence, the excreta (dung or gobar) of cattle is rich in these bacteria and thus used for generation of biogas (gobar gas).