Which one of the following bacterium is used extensively as biopesticide?

Options

A. Bacillus subtilis
B. Streptococcus lactis
C. Bacillus thuringenesis
D. Lactobacillus acidophilus

Answer

**Step-by-Step Solution:**

1. **Understanding Biopesticides**: Biopesticides are natural organisms or substances derived from them that are used to control pests and insects. They are considered environmentally friendly alternatives to chemical pesticides.

2. **Analyzing the Options**:
- **Option 1: Bacillus subtilis**: This bacterium is known for its safety and is often used in agriculture but does not specifically target pests. Therefore, it is not suitable as a biopesticide.
- **Option 2: Streptococcus lactis**: This bacterium is primarily used in the dairy industry for the production of buttermilk and cheese. It does not have properties that make it effective against pests, so it cannot be classified as a biopesticide.
- **Option 3: Bacillus thuringiensis (Bt)**: This bacterium is widely recognized as a biopesticide. It produces a protein (Cry protein) that is toxic to certain insects, making it effective for pest control.
- **Option 4: Lactobacillus acidophilus**: This bacterium is known for its role in fermentation and is commonly found in yogurt. It thrives in acidic environments and is not related to pest control, thus it is not a biopesticide.

3. **Conclusion**: After evaluating all the options, the only bacterium that is extensively used as a biopesticide is **Bacillus thuringiensis**.

**Final Answer**: The correct answer is **Option 3: Bacillus thuringiensis**.

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