9 min readConcept sheet1-mark MCQ matching a product with its microbe, a 2 or 3-mark question on enzymes and bioactive molecules; also a NEET favourite

Microbes in industrial production

Grown in huge fermentors, microbes make beverages, organic acids, ethanol, enzymes and medicines such as streptokinase, cyclosporin A and statins.

FermentorA very large vessel for growing microbes on an industrial scale

Brewer's yeastSaccharomyces cerevisiae; ferments malted cereals and fruit juices to make ethanol

Citric acidMade by the fungus Aspergillus niger

StatinsFrom the yeast Monascus purpureus; lower blood cholesterol by competitively inhibiting the enzyme that makes cholesterol

Fermented beverages: with and without distillation

Without distillationWine and beer. Brewer's yeast (Saccharomyces cerevisiae, the same species as baker's yeast) ferments fruit juices or malted cereals into ethanol, and the drink is used without distilling.

With distillationWhisky, brandy and rum. The fermented broth is distilled. The raw material and the processing decide the type of drink.

Organic acids and alcohol

Product	Microbe	Type of microbe
Citric acid	Aspergillus niger	Fungus
Acetic acid	Acetobacter aceti	Bacterium
Butyric acid	Clostridium butylicum	Bacterium
Lactic acid	Lactobacillus	Bacterium
Ethanol	Saccharomyces cerevisiae	Yeast (fungus)

Enzymes and bioactive molecules

Product	Source	Use
Lipases	Microbes	In detergents; remove oily stains from laundry
Pectinases and proteases	Microbes	Clarify bottled fruit juices, so they are clearer than home-made juice
Streptokinase	Bacterium Streptococcus, modified by genetic engineering	'Clot buster': removes clots from blood vessels of patients after myocardial infarction (heart attack)
Cyclosporin A	Fungus Trichoderma polysporum	Immunosuppressive agent for organ-transplant patients
Statins	Yeast Monascus purpureus	Lower blood cholesterol

Why use microbes in industry? (extra, not in your textbook)

Microbes multiply very fast, grow on cheap raw materials such as molasses and cereals, and each kind makes a specific product. In a fermentor, temperature, pH, oxygen and nutrients are controlled so the microbes give a large, steady yield. Genetic engineering can improve a microbe's product, as with streptokinase.

In real life

Vinegar (acetic acid) in pickles, citric acid in packaged drinks, and lipase in washing powder are all made by microbes. Doctors may prescribe statins to people with high cholesterol, a common health problem in India.

Exam angle

2 marks: “Name the microbes used to produce citric acid and statins. How do statins lower blood cholesterol?” Citric acid: Aspergillus niger. Statins: Monascus purpureus. Statins competitively inhibit the enzyme responsible for synthesis of cholesterol.

3 marks: “Give the source and one use each of streptokinase, cyclosporin A and lipase.” Streptokinase: Streptococcus (genetically modified); clot buster after heart attack. Cyclosporin A: Trichoderma polysporum; immunosuppressant in organ transplants. Lipase: microbes; removes oily stains in detergents.

2 marks: “Why are bottled fruit juices clearer than juices made at home? How is whisky different from beer in production?” Bottled juices are clarified with pectinases and proteases. Whisky is made by distilling the fermented broth; beer is made without distillation.

Remember it

Aspergillus = Acid of citrus; Acetobacter = Acetic; Clostridium butylicum = butyric; Streptococcus = Streptokinase; Monascus = monitors cholesterol.