Citric acid is obtained from (A) Aspergillus niger (B) Rhizobium nigricans (C) Penicillium citrinum (D) Lactobacillus vulgaricus

Options

A. Aspergillus niger
B. Rhizobium nigricans
C. Penicillium citrinum
D. Lactobacillus vulgaricus

Answer

To solve the question "Citric acid is obtained from," we need to analyze the options provided and identify which organism is known for producing citric acid.

### Step-by-Step Solution:

1. **Understanding Citric Acid**:
- Citric acid is an organic acid that is widely used in the food and pharmaceutical industries. It is produced through fermentation processes.

2. **Identifying the Fermentation Process**:
- The production of citric acid typically occurs through a method known as submerged fermentation, where microorganisms are grown in a liquid medium that contains nutrients.

3. **Evaluating the Options**:
- (A) **Aspergillus niger**: This is a fungus that is well-known for its ability to produce citric acid.
- (B) **Rhizobium nigricans**: This is a type of bacteria primarily associated with nitrogen fixation in legumes, not citric acid production.
- (C) **Penicillium citrinum**: While this fungus is known for producing citrinin, it is not the primary source of citric acid.
- (D) **Lactobacillus vulgaricus**: This is a bacterium used in fermentation processes, particularly for dairy products, but not for citric acid.

4. **Conclusion**:
- Based on the information, the correct answer is **(A) Aspergillus niger**, as it is the organism primarily used for the production of citric acid.

### Final Answer:
**(A) Aspergillus niger**

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