Question

Citric acid is obtained from?

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

Answer 1

Hint: Microbes are also used for commercial and industrial production of certain chemicals like organic acids, alcohols, and enzymes. Different bacteria produce different substances like Clostridium butylicum produces butyric acid.
Complete step-by-step answer:
Different organisms like Aspergillus niger ( a fungus) of citric acid , Acetobacter aceti (a bacterium) also produces acetic acid. The molecules that are functional in a living system or can interact with their components are called Bioactive molecules like organic acids, enzymes, cyclosporin A and statins.
Certain microbes can convert carbohydrates into organic acids. Cyclosporin is used as an immunosuppressive agent in the organ transplant patient. Statins are produced by yeast that has been commercialized as blood-cholesterol-lowering agents.
Lactobacillus vulgaricus (a bacterium) helps in the production of lactic acid. Penicillium citrinum is a species of a genus of Penicillium that is an anamorph, the mesophilic fungus that produces Tanzania acid A-D, ACC, Mevastatin, Quinocitrinine A, Quinocitrinine B.
Rhizobium nigricans is a diazotrophic bacteria that fix nitrogen after becoming established inside the nodules of legumes. Rhizobia require a plant host to express their nitrogen fixation. They are gram negative, motile, non- sporulating rods.

Therefore the correct answer is Option A.
Note: Natural sources of acetic acid include apples, grapes, pineapple, strawberries, and oranges. Acetic acid can also be found in vinegar. Vinegar and certain natural rotting fruits and vegetables are natural sources of acetic acid. So we can say that the main natural source of acetic acid is vinegar.