Biology · Microbes in Human Welfare · NEET
NCERT lists exactly four acid producers, and NEET tests them almost every year. Aspergillus niger (a fungus) makes citric acid. Acetobacter aceti (a bacterium) makes acetic acid. Clostridium butylicum (a bacterium) makes butyric acid. Lactobacillus (a bacterium) makes lactic acid. Only citric acid comes from a fungus; the other three come from bacteria. Trick: 'Citric is the odd one, it is Fungal.'
Cyclosporin A is produced by the fungus Trichoderma polysporum. It is used as an immunosuppressive agent, meaning it lowers the body's immune response so a transplanted organ is not rejected. NEET loves to swap this source with Clostridium or Aspergillus, so lock it: Trichoderma to cyclosporin to organ transplant.
Statins are produced by the yeast Monascus purpureus. They are commercial blood-cholesterol lowering agents. They work by competitively inhibiting the enzyme responsible for cholesterol synthesis. Both statins and ethanol involve a yeast, but ethanol is from Saccharomyces cerevisiae and statins are from Monascus purpureus, so do not mix the two yeasts.
Streptokinase is produced by the bacterium Streptococcus and is modified by genetic engineering. It works as a 'clot buster' to remove clots from the blood vessels of patients who have had a myocardial infarction (heart attack). Do not confuse the name with Streptomyces (which gives antibiotics). Streptococcus to streptokinase to clot removal.
Saccharomyces cerevisiae, the same brewer's/baker's yeast, is used here for commercial production of ethanol. It is a yeast, like Monascus purpureus (statins), but the two do different jobs. Remember: Saccharomyces to ethanol, Monascus to statins.
These are microbial enzymes. Lipases are used in detergent formulations to remove oily stains from laundry. Pectinases and proteases are used to clarify bottled fruit juices, which is why market juice looks clearer than home juice. A common NEET trap wrongly links lipase to an acid producer like Clostridium; lipase is an enzyme, not an acid.
Which of the following is wrongly matched in the given table (Microbe – Product – Application)?
Identify the microorganism which is responsible for the production of an immunosuppressive molecule cyclosporin A:
Match List I with List II. A. Clostridium butylicum, B. Saccharomyces cerevisiae, C. Trichoderma polysporum, D. Streptococcus sp.; I. Ethanol, II. Streptokinase, III. Butyric acid, IV. Cyclosporin-A.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Citric acid is from a fungus, Aspergillus niger. It is the only acid producer in the NCERT list that is a fungus; acetic, butyric and lactic acids all come from bacteria.
Ethanol comes from the yeast Saccharomyces cerevisiae, and statins come from the yeast Monascus purpureus. Keep the two yeasts separate.
Streptokinase, from the bacterium Streptococcus, dissolves blood clots in patients who have had a heart attack (myocardial infarction), so it 'busts' the clot blocking a vessel.
No. Cyclosporin A is an immunosuppressive agent used in organ transplants, produced by Trichoderma polysporum. It is a bioactive molecule, not an antibiotic.
Statins act by competitively inhibiting the enzyme responsible for the synthesis of cholesterol in the body, so less cholesterol is made.
