Filamentous blue green alga used as SCP among the following

Options

A. Brevibacterium
B. Methylophillus
C. Spirulina
D. Yeast

Answer

To determine the filamentous blue-green alga used as single-cell protein (SCP), we can analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a filamentous blue-green alga that is used as single-cell protein (SCP).

2. **Analyzing the Options**:
- **Option 1: Brevi bacterium**: This is a type of bacteria, not an alga. Therefore, it cannot be the answer.
- **Option 2: Methylophilus**: This is also a type of bacteria found in animal guts. It is not an alga, so it is not the correct answer.
- **Option 3: Spirulina**: This is a filamentous blue-green alga (cyanobacteria) that is well-known for its high protein content and is commonly used as a source of single-cell protein.
- **Option 4: Yeast**: Yeast is a fungus, not an alga. It is used in various fermentation processes but does not fit the criteria of being a blue-green alga.

3. **Identifying the Correct Answer**: Based on the analysis, the only option that is both a filamentous blue-green alga and used as SCP is **Spirulina**.

4. **Conclusion**: The correct answer to the question is **Option 3: Spirulina**.