Question

Which of the following microorganisms is used in the production of curd from milk?

• A. Saccharomyces cerevisiae
• B. Lactobacillus acidophilus
• C. Aspergillus niger
• D. Penicillium notatum

Hint:

For microbial processes, associate *Lactobacillus* species with dairy fermentation (curd, yogurt), *Saccharomyces* with baking or alcohol, and *Penicillium* or *Aspergillus* with antibiotics or industrial products.

Answer 1

The Correct Option is B

The production of curd from milk involves the fermentation of lactose (milk sugar) into lactic acid by specific bacteria. Lactobacillus acidophilus, along with other lactic acid bacteria such as *Lactobacillus delbrueckii* subsp. *bulgaricus* and *Streptococcus thermophilus*, is commonly used in this process. These bacteria convert lactose into lactic acid, which lowers the pH, causing milk proteins (casein) to coagulate and form curd.
The other options have different roles:
- Saccharomyces cerevisiae: A yeast used in baking (bread production) and alcohol fermentation (e.g., wine, beer).
- Aspergillus niger: A fungus used in the production of citric acid and certain enzymes, not curd.
- Penicillium notatum: A fungus used in the production of the antibiotic penicillin, not involved in curd formation.
Thus, the microorganism used in the production of curd from milk is *Lactobacillus acidophilus*.