Methanogens, growing anaerobically on cellulosic material produce

Options

A. methane
B. methane and carbon dioxide
C. methane and hydrogen
D. methane, carbon dioxide and hydrogen

Answer

### Step-by-Step Solution:

1. **Understanding Methanogens**:
- Methanogens are a type of microorganism that belong to the domain Archaea. They are prokaryotic organisms known for their ability to produce methane.

2. **Anaerobic Conditions**:
- Methanogens thrive in anaerobic (absence of oxygen) environments. They are commonly found in places like swamps, marshes, and the intestines of animals, where organic matter is abundant.

3. **Substrate for Methanogens**:
- In this question, we focus on methanogens growing on cellulosic material. Cellulosic materials are organic compounds made primarily of cellulose, which is a major component of plant cell walls.

4. **Metabolic Process**:
- Under anaerobic conditions, methanogens break down organic matter, including cellulosic materials. This process involves the fermentation of organic substrates, leading to the production of various gases.

5. **Gases Produced**:
- The primary gas produced by methanogens is methane (CH₄). However, during the breakdown of organic matter, they also produce carbon dioxide (CO₂) and small amounts of hydrogen (H₂).

6. **Conclusion**:
- Therefore, when methanogens act on cellulosic material anaerobically, they produce a mixture of gases: methane, carbon dioxide, and hydrogen. The correct answer to the question is option D: "methane, carbon dioxide, and hydrogen."

### Final Answer:
- Methanogens growing anaerobically on cellulosic material produce **methane, carbon dioxide, and hydrogen**.

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