Which of the following is not an antibiotic produced by bacteria ?

Options

A. Bacitracin
B. Polymyxin A
C. Griseofulvin
D. Amphotericin B

Answer

To solve the question "Which of the following is not an antibiotic produced by bacteria?" we will analyze each of the given options to determine their origins and classifications.

### Step-by-Step Solution:

1. **Understanding Antibiotics**:
- Antibiotics are substances that inhibit the growth of or destroy bacteria. They can be derived from various sources, including bacteria and fungi.

2. **Analyzing Option A: Bacteriocin**:
- Bacteriocins are antimicrobial peptides produced by bacteria, specifically from species like *Bacillus subtilis*. Therefore, this is an antibiotic produced by bacteria.

3. **Analyzing Option B: Polymyxin**:
- Polymyxin B is an antibiotic that is used to treat bacterial infections. It is derived from *Bacillus polymyxa*, which confirms that it is also produced by bacteria.

4. **Analyzing Option C: Grysofulvin**:
- Grysofulvin is not an antibiotic; it is an antifungal agent used to treat fungal infections, particularly of the skin and nails. It is derived from the mold *Penicillium griseofulvum*, which means it is not produced by bacteria.

5. **Analyzing Option D: Amphotericin**:
- Amphotericin B is another antifungal agent, but it is derived from the bacterium *Streptomyces nodosus*. Thus, it is produced by bacteria.

6. **Conclusion**:
- Since Grysofulvin is the only option that is not an antibiotic produced by bacteria, the correct answer is **C. Grysofulvin**.

### Final Answer:
C. Grysofulvin