Which of the following is incorrect about methanogens ?

Options

A. They are archaebacteria .
B. They live in marshy area.
C. Methane is their preferred carbon source .
D. They persist in guts of several ruminate animals and they produces biogas from their dung.

Answer

To determine which statement about methanogens is incorrect, let's analyze each option step by step:

1. **Understanding Methanogens**:
- Methanogens are a group of microorganisms that belong to the domain Archaea. They are known for producing methane as a metabolic by-product, primarily through the process of anaerobic respiration.

2. **Evaluating the Options**:
- **Option 1**: "They are archaebacteria."
- This statement is correct. Methanogens are indeed classified as archaebacteria (or archaea), which are distinct from bacteria.

- **Option 2**: "They live in the marshy area."
- This statement is also correct. Methanogens thrive in anaerobic environments such as marshy areas, where they can produce methane.

- **Option 3**: "Methane is their preferred carbon source."
- This statement is incorrect. Methanogens do not use methane as their carbon source; instead, they utilize carbon dioxide (CO2) and hydrogen (H2) to produce methane. Therefore, this is the incorrect statement.

- **Option 4**: "They persist in the gut of several ruminant animals and they produce biogas from their dung."
- This statement is correct. Methanogens are found in the digestive tracts of ruminant animals (like cows and sheep) and play a role in producing biogas from their digestive processes.

3. **Conclusion**:
- The incorrect statement about methanogens is **Option 3**: "Methane is their preferred carbon source."