Which of the following microbes in used for commercial production of ethanol ?

Options

A. Closteridium butylium
B. Streptococcus
C. Trichoderma polysporum
D. Saccharmyces cerevisiae

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which microbe is used for the commercial production of ethanol. Ethanol is commonly produced through fermentation processes.

2. **Analyzing the Options**:
- **Clostridium butylicum**: This bacterium is primarily known for the production of butyric acid, not ethanol.
- **Streptococcus**: This genus produces streptokinase, an enzyme used as a clot buster, and is not involved in ethanol production.
- **Trichoderma polysporum**: This fungus produces cyclosporine A, an immunosuppressive agent, and is not related to ethanol production.
- **Saccharomyces cerevisiae**: This is a type of yeast that is well-known for its role in fermentation, particularly in converting sugars into ethanol.

3. **Identifying the Correct Answer**: Among the options provided, Saccharomyces cerevisiae is the only microbe that is used for the commercial production of ethanol through the fermentation of sugars.

4. **Conclusion**: The correct answer to the question is **Saccharomyces cerevisiae**.

**Final Answer**: Saccharomyces cerevisiae

---