Who showed that yeast causes fermentation to produce beer and buttermilk

Options

A. (a) Louis Pasteur
B. (b) Buchner
C. (c) Kuhne
D. (d) Cruickshan

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks who demonstrated that yeast causes fermentation, specifically in the production of beer and buttermilk.

2. **Identifying Key Scientists:** The options provided in the question likely include notable scientists in microbiology and fermentation. The key figures to consider are Louis Pasteur, Eduard Buchner, Kuhne, and Cruikshank.

3. **Researching Louis Pasteur:** Louis Pasteur is known for his pioneering work in microbiology. In 1857, he conducted experiments that demonstrated the role of yeast in fermentation. He observed the production of carbon dioxide (CO2) bubbles during the fermentation process, which indicated that yeast was responsible for converting sugars into alcohol and acids.

4. **Understanding Fermentation:** Fermentation is an anaerobic process where glucose is converted into pyruvate and then into either ethanol (in alcoholic fermentation) or lactic acid (in lactic acid fermentation). Pasteur's work showed that yeast, specifically the species Saccharomyces cerevisiae, is vital in this process.

5. **Evaluating Other Scientists:**
- **Eduard Buchner:** He showed that enzymes from yeast are responsible for fermentation, not the yeast cells themselves, in 1907, which is not what the question asks.
- **Kuhne:** He coined the term "enzyme," but did not demonstrate fermentation.
- **Cruikshank:** His contributions were primarily in cancer research, unrelated to fermentation.

6. **Conclusion:** Based on the evidence, the correct answer to the question is Louis Pasteur, as he was the first to demonstrate that yeast causes fermentation to produce beer and buttermilk.

**Final Answer:** Louis Pasteur

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