Largest among sulpher bacteria are

Options

A. Chlorobium
B. Beggiatoa
C. Chromatium
D. Thiobacillus

Answer

To solve the question "Largest among sulfur bacteria are?", we can follow these steps:

### Step 1: Understand the Question
The question is asking for the largest type of sulfur bacteria. We need to identify the correct genus from the given options.

### Step 2: Analyze the Options
We have four options to consider:
1. **Chlorobium**
2. **Beggiatoa**
3. **Chromatium**
4. **Thiohalobacter**

### Step 3: Evaluate Each Option
- **Chlorobium**: This is a genus of green sulfur bacteria that are photolithotropic. They are relatively small, with sizes less than 10 micrometers in length. Therefore, this option is incorrect.

- **Beggiatoa**: This genus is known for being filamentous and colorless proteobacteria. They can grow up to 200 micrometers in length, making them the largest among sulfur bacteria. This option is correct.

- **Chromatium**: This genus is associated with photoautotrophic gram-negative bacteria found in aquatic environments. They are not the largest, so this option is incorrect.

- **Thiohalobacter**: This is a genus of gram-negative proteobacteria, but they are not known for being large. Thus, this option is also incorrect.

### Step 4: Conclusion
After evaluating all options, we find that **Beggiatoa** is the largest among sulfur bacteria, with sizes reaching up to 200 micrometers.

### Final Answer
The largest among sulfur bacteria are **Beggiatoa**.

---