How many of the following organisms are associated with the production of single - cell protein ?
Yeast , Chlorella, Sprirulina , Nostoc, Methylophilus methylotrophus, Mushroom, Clostridium

Options

A. Two
B. Five
C. Four
D. Three

Answer

To determine how many of the listed organisms are associated with the production of single-cell protein (SCP), we will analyze each organism one by one.

1. **Yeast**: Yeasts are a well-known source of single-cell protein. They can be cultivated on various substrates and have high protein content. Thus, yeast is associated with SCP.

2. **Chlorella**: Chlorella is a type of green algae that is rich in protein and is often used as a dietary supplement. It is also associated with the production of single-cell protein.

3. **Spirulina**: Spirulina is a blue-green algae (cyanobacteria) that is highly nutritious and contains a significant amount of protein. It is widely recognized as a source of single-cell protein.

4. **Nostoc**: Nostoc is a genus of cyanobacteria that can also be used as a source of protein. It is less common than Spirulina and Chlorella but can still contribute to SCP production.

5. **Methylophilus methylotrophus**: This is a type of bacteria that can utilize methanol as a carbon source and is known for its high protein yield. It is associated with the production of single-cell protein.

6. **Mushroom**: Mushrooms are fungi and are not typically classified as single-cell protein sources. They are multicellular organisms and do not fit the definition of SCP.

7. **Clostridium**: Clostridium is a genus of bacteria that includes some pathogenic species. While some species can produce protein, they are not primarily known for SCP production.

Now, let's summarize the findings:

- Yeast: Yes (SCP source)
- Chlorella: Yes (SCP source)
- Spirulina: Yes (SCP source)
- Nostoc: Yes (SCP source)
- Methylophilus methylotrophus: Yes (SCP source)
- Mushroom: No (not an SCP source)
- Clostridium: No (not primarily an SCP source)

Thus, the organisms associated with the production of single-cell protein are:
1. Yeast
2. Chlorella
3. Spirulina
4. Nostoc
5. Methylophilus methylotrophus

Total: 5 organisms.

**Final Answer**: 5