Which one of the following pairs is not correctly matched

Options

A. Spirulina - Single cell protein
B. Rhizobium - Biofertilizer
C. Streptomyces - Antibiotic
D. Serratia - Drug addiction

Explanation

To determine which pair is not correctly matched, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the pairs:**
- Pair 1: Spirulina - Single Cell Protein
- Pair 2: Rhizobium - Biofertilizers
- Pair 3: Streptomyces - Antibiotics
- Pair 4: Seratia - Drug Addiction

2. **Evaluate each pair:**
- **Spirulina - Single Cell Protein:**
- Spirulina is indeed a type of cyanobacteria that is rich in protein and is used as a source of single-cell protein.
- **Conclusion:** This pair is correctly matched.

- **Rhizobium - Biofertilizers:**
- Rhizobium is a symbiotic bacterium that fixes atmospheric nitrogen in the root nodules of leguminous plants, thus acting as a biofertilizer.
- **Conclusion:** This pair is correctly matched.

- **Streptomyces - Antibiotics:**
- Streptomyces is a genus of bacteria known for producing a variety of antibiotics, including streptomycin.
- **Conclusion:** This pair is correctly matched.

- **Seratia - Drug Addiction:**
- Seratia is a genus of gram-negative bacteria, and it does not cause drug addiction. This is a misrepresentation.
- **Conclusion:** This pair is not correctly matched.

3. **Final Answer:**
- The pair that is not correctly matched is **Seratia - Drug Addiction**. Therefore, the correct answer is option number 4.