- A Lactobacillus
- B Saccharomyces
- C Aspergillus niger
- D Streptococcus
Correct answer: C. Aspergillus niger
Explanation: Aspergillus niger, a fungus, is used for the commercial production of citric acid.
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers