Methanogens convert

Options

A. Methyl alcohol into methane
B. Formic acid into methane
C. Acetic acid into methane
D. All the above

Answer

### Step-by-Step Solution:

1. **Understanding Methanogens**: Methanogens are a type of archaea that produce methane as a metabolic byproduct in anoxic conditions. They play a crucial role in the process of biogas formation.

2. **Biogas Formation Process**: The biogas formation involves three main processes:
- **Solubilization**: In this initial step, complex organic materials (polymers) are broken down into simpler compounds (monomers).
- **Acetogenesis**: The monomers are then converted into organic acids, primarily acetic acid, by fermentative microbes.
- **Methanogenesis**: Finally, methanogens convert these organic acids into methane.

3. **Identifying the Organic Acids**: The question asks which compounds methanogens can convert into methane. The options given are:
- Methyl alcohol
- Formic acid
- Acetic acid
- All of the above

4. **Analyzing Each Option**:
- **Methyl Alcohol to Methane**: Methanogens do not typically convert methyl alcohol directly into methane.
- **Formic Acid to Methane**: While some methanogens can convert formic acid to methane, it is not the primary substrate.
- **Acetic Acid to Methane**: Acetic acid is the most common substrate for methanogens and is efficiently converted into methane.

5. **Conclusion**: Since acetic acid is the primary substrate that methanogens convert into methane, the correct answer is:
- **Acetic acid into methane** (Option 3).

### Final Answer:
**Acetic acid into methane** (Option 3).

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