Microbes in Everyday Life and Industry

Microbes in Everyday Life and Industry

Microbes are microscopic organisms that include bacteria, fungi, protozoans, microscopic algae and some viruses. Many microbes are useful to humans and play important roles in food production, medicine, agriculture, waste management and industries.

हर microbe harmful नहीं होता। बहुत-से microorganisms हमारे daily life में useful products बनाने और ecological processes में important role निभाते हैं।

1. Microbes in Household Products

Microorganisms have been used by humans for thousands of years in the preparation of fermented food and beverages.

Curd

Curd is prepared from milk with the help of Lactic Acid Bacteria (LAB), mainly Lactobacillus.

LAB milk में मौजूद lactose को lactic acid में convert करते हैं। Lactic acid milk proteins को coagulate करके curd formation में मदद करता है।

LAB also improve the nutritional quality of curd by increasing the availability of certain nutrients, including vitamin B₁₂.

Idli and Dosa

The dough used for preparing idli and dosa undergoes fermentation due to the activity of microorganisms.

Fermentation makes the dough soft and increases its volume. इससे food की texture और digestibility बेहतर होती है।

Cheese

Different microorganisms are used in the production and ripening of different types of cheese.

Microorganism	Product / Use
Propionibacterium shermanii	Swiss cheese
Penicillium roqueforti	Roquefort cheese

Propionibacterium shermanii produces carbon dioxide during cheese production, which contributes to the characteristic holes in Swiss cheese.

Traditional Fermented Beverages

Microorganisms are also used in the production of alcoholic beverages.

Saccharomyces cerevisiae, commonly called brewer's yeast, is widely used for fermentation.

Yeast converts sugars into ethanol and carbon dioxide under anaerobic conditions.

2. Microbes in Industrial Production

Microbes are used on a large scale to manufacture commercially valuable products. Such production is carried out in large vessels called fermenters.

A fermenter provides controlled conditions such as temperature, pH, oxygen supply and nutrient availability for microbial growth and product formation.

3. Industrial Products from Microbes

Microbes are used to produce:

• Alcohols
• Organic acids
• Antibiotics
• Enzymes
• Bioactive molecules

Important Microbial Products

Microorganism	Product
Aspergillus niger	Citric acid
Acetobacter aceti	Acetic acid
Clostridium butylicum	Butyric acid
Lactobacillus	Lactic acid
Saccharomyces cerevisiae	Ethanol

4. Antibiotics

Antibiotics are chemical substances produced by certain microorganisms that can kill or inhibit the growth of other microorganisms.

Antibiotics have played a major role in the treatment of bacterial infections.

Penicillin

Penicillin was one of the first widely used antibiotics.

It was discovered by Alexander Fleming in 1928 while studying the bacterium Staphylococcus.

Fleming observed that a mould growing on his bacterial culture prevented bacterial growth around it. The mould was identified as Penicillium notatum.

5. Other Important Microbial Products

Streptokinase

Streptokinase is produced by the bacterium Streptococcus and is used as a clot buster in certain medical situations.

It helps dissolve blood clots by activating plasminogen to form plasmin.

Cyclosporin A

Cyclosporin A is produced by the fungus Trichoderma polysporum.

It is used as an immunosuppressive agent, particularly in organ transplantation, to reduce rejection of transplanted organs.

Statins

Statins are cholesterol-lowering compounds produced by certain microorganisms.

Monascus purpureus produces statins, which inhibit an enzyme involved in cholesterol synthesis.

6. Microbes in Sewage Treatment

Sewage is wastewater containing human excreta and other organic matter. Microorganisms play an important role in treating sewage before it is released into the environment.

Primary Treatment

Primary treatment is mainly a physical process.

Large particles are removed by processes such as filtration and sedimentation.

Secondary Treatment

Secondary treatment is mainly a biological process in which microorganisms degrade organic matter present in sewage.

Activated Sludge

During secondary treatment, the effluent is aerated in large aeration tanks. Aerobic microbes grow rapidly and form flocs.

Flocs are masses of bacteria associated with fungal filaments that form a mesh-like structure.

These microbial flocs consume organic matter and reduce the Biochemical Oxygen Demand (BOD) of the sewage.

7. BOD

BOD (Biochemical Oxygen Demand) is the amount of dissolved oxygen required by microorganisms to decompose the organic matter present in a water sample.

High BOD indicates a high amount of biodegradable organic matter.

जब sewage में organic matter अधिक होता है, तो microbes उसे decompose करने के लिए अधिक oxygen consume करते हैं। इसलिए BOD अधिक होता है।

Sludge Digestion

The microbial flocs are allowed to settle, producing a sediment called activated sludge.

A portion of activated sludge is returned to the aeration tank as inoculum, while the remaining sludge is transferred to anaerobic sludge digesters.

In anaerobic digesters, anaerobic bacteria produce gases such as methane, carbon dioxide and hydrogen sulphide.

8. Biogas

Biogas is a mixture of gases produced by the anaerobic decomposition of organic matter.

The major component of biogas is methane (CH₄).

Methanogens

Methanogens are anaerobic microorganisms that produce methane during the decomposition of organic matter.

An important methanogen is Methanobacterium.

Methanogens are commonly found in anaerobic environments such as marshy areas and the rumen of cattle.

9. Biogas Plant

Biogas plants are commonly used in rural areas to produce fuel from cattle dung and other organic waste.

The partially digested slurry from cattle dung is fed into an anaerobic digester. Methanogenic microorganisms act on the organic material and produce biogas.

Major Steps

1. Cattle dung and water are mixed to form slurry.
2. The slurry is introduced into the digester.
3. Anaerobic microbes decompose organic matter.
4. Methanogens produce methane-rich biogas.
5. Biogas is collected and used as fuel.
6. The remaining slurry can be used as manure.

10. Microbes as Biofertilisers

Biofertilisers are organisms that enrich the nutrient quality of soil.

They are useful alternatives or supplements to chemical fertilisers and can improve soil fertility.

Rhizobium

Rhizobium is a symbiotic bacterium associated with the root nodules of leguminous plants.

It fixes atmospheric nitrogen into forms that can be utilised by plants.

Root nodules में Rhizobium और legume plant के बीच symbiotic relationship होता है। Plant bacteria को food और suitable environment देता है, जबकि bacteria nitrogen fixation में मदद करता है।

Azospirillum and Azotobacter

Azospirillum and Azotobacter are free-living nitrogen-fixing bacteria that can contribute to soil nitrogen enrichment.

Mycorrhiza

Mycorrhiza is a symbiotic association between certain fungi and plant roots.

One important example is Glomus.

Mycorrhizal association helps plants in the absorption of phosphorus and can improve resistance to drought and some soil pathogens.

11. Cyanobacteria as Biofertilisers

Some cyanobacteria are capable of fixing atmospheric nitrogen and are important biofertilisers, especially in paddy fields.

Examples include:

• Anabaena
• Nostoc

These organisms enrich soil with nitrogen and can improve soil fertility.

12. Important Microbes and Their Uses

Microorganism	Product / Role
Lactobacillus	Curd / lactic acid
Saccharomyces cerevisiae	Alcoholic fermentation
Propionibacterium shermanii	Swiss cheese
Penicillium roqueforti	Roquefort cheese
Aspergillus niger	Citric acid
Acetobacter aceti	Acetic acid
Clostridium butylicum	Butyric acid
Streptococcus	Streptokinase
Trichoderma polysporum	Cyclosporin A
Monascus purpureus	Statins
Methanobacterium	Biogas production
Rhizobium	Nitrogen fixation
Glomus	Mycorrhizal association
Anabaena	Nitrogen fixation

13. Important Differences

Primary Treatment vs Secondary Treatment

Primary Treatment	Secondary Treatment
Mainly physical	Mainly biological
Removes large and suspended particles	Microorganisms degrade organic matter
Filtration and sedimentation are important	Aeration and microbial activity are important

Antibiotics vs Biofertilisers

Antibiotics	Biofertilisers
Used mainly to control microorganisms causing disease	Used to improve soil fertility
Example: Penicillin	Example: Rhizobium

14. Board Important Questions

Very Short Answer Questions

1. What are microbes?
2. Name the bacterium mainly responsible for curd formation.
3. What is the role of Lactobacillus in curd?
4. Name the microorganism used in Swiss cheese.
5. Name the microorganism used in Roquefort cheese.
6. What is the scientific name of brewer's yeast?
7. Who discovered penicillin?
8. Name the fungus from which penicillin was discovered.
9. What is a fermenter?
10. Name the microorganism used to produce citric acid.
11. What is streptokinase?
12. Name the microorganism that produces Cyclosporin A.
13. What are statins?
14. What is BOD?
15. What are flocs?
16. What are methanogens?
17. Name the major component of biogas.
18. Name one methanogenic bacterium.
19. What is a biofertiliser?
20. Name one symbiotic nitrogen-fixing bacterium.

Short Answer Questions

1. Explain the role of Lactobacillus in curd formation.
2. Explain the role of microbes in the preparation of cheese.
3. Describe alcoholic fermentation by Saccharomyces cerevisiae.
4. What are fermenters? Why are they used in industries?
5. Write a note on penicillin and its discovery.
6. Explain the importance of streptokinase.
7. What are statins? Mention their source and use.
8. Explain the role of microbes in sewage treatment.
9. What are flocs? How are they formed?
10. What is BOD? Why is it important in sewage treatment?
11. Explain the role of methanogens in biogas production.
12. Describe the working of a biogas plant.
13. What are biofertilisers? Give suitable examples.
14. Explain the role of Rhizobium as a biofertiliser.
15. What is mycorrhiza? Mention its importance.

Long Answer Questions

1. Describe the various useful activities of microbes in household products.
2. Explain the role of microorganisms in industrial production with suitable examples.
3. Describe the process of secondary sewage treatment and explain the role of microbes.
4. Explain the production of biogas and the role of methanogens.
5. Describe the role of microbes as biofertilisers with suitable examples.

15. Multiple Choice Questions

1. Curd is mainly produced with the help of:
   (A) Rhizobium
   (B) Lactobacillus
   (C) Methanobacterium
   (D) Penicillium
   Answer: (B) Lactobacillus
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2. Swiss cheese is produced with the help of:
   (A) Propionibacterium shermanii
   (B) Lactobacillus
   (C) Aspergillus niger
   (D) Monascus purpureus
   Answer: (A) Propionibacterium shermanii
3. Brewer's yeast is:
   (A) Saccharomyces cerevisiae
   (B) Rhizobium
   (C) Anabaena
   (D) Methanobacterium
   Answer: (A) Saccharomyces cerevisiae
4. Penicillin was discovered by:
   (A) Louis Pasteur
   (B) Alexander Fleming
   (C) Robert Koch
   (D) Edward Jenner
   Answer: (B) Alexander Fleming
5. Citric acid is produced commercially using:
   (A) Aspergillus niger
   (B) Rhizobium
   (C) Methanobacterium
   (D) Streptococcus
   Answer: (A) Aspergillus niger
6. Streptokinase is used as:
   (A) Biofertiliser
   (B) Clot buster
   (C) Antibiotic
   (D) Vaccine
   Answer: (B) Clot buster
7. Cyclosporin A is produced by:
   (A) Trichoderma polysporum
   (B) Monascus purpureus
   (C) Aspergillus niger
   (D) Lactobacillus
   Answer: (A) Trichoderma polysporum
8. Statins are produced by:
   (A) Monascus purpureus
   (B) Rhizobium
   (C) Saccharomyces cerevisiae
   (D) Anabaena
   Answer: (A) Monascus purpureus
9. BOD stands for:
   (A) Biological Oxygen Division
   (B) Biochemical Oxygen Demand
   (C) Bacterial Oxygen Demand
   (D) Biochemical Organic Decomposition
   Answer: (B) Biochemical Oxygen Demand
10. Flocs formed during secondary sewage treatment mainly contain:
    (A) Bacteria and fungal filaments
    (B) Viruses only
    (C) Algae only
    (D) Protozoans only
    Answer: (A) Bacteria and fungal filaments
11. The major component of biogas is:
    (A) Oxygen
    (B) Nitrogen
    (C) Methane
    (D) Hydrogen
    Answer: (C) Methane
12. Methanogens are:
    (A) Aerobic fungi
    (B) Anaerobic microorganisms producing methane
    (C) Disease-causing viruses
    (D) Photosynthetic plants
    Answer: (B) Anaerobic microorganisms producing methane
13. Rhizobium is important because it:
    (A) Produces alcohol
    (B) Fixes atmospheric nitrogen
    (C) Produces penicillin
    (D) Produces methane
    Answer: (B) Fixes atmospheric nitrogen
14. Mycorrhiza is an association between:
    (A) Bacteria and animals
    (B) Fungi and plant roots
    (C) Viruses and plants
    (D) Algae and animals
    Answer: (B) Fungi and plant roots
15. Which of the following is a cyanobacterial biofertiliser?
    (A) Anabaena
    (B) Penicillium
    (C) Saccharomyces
    (D) Aspergillus
    Answer: (A) Anabaena
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16. Fill in the Blanks

1. Curd is prepared with the help of ______.
2. Swiss cheese is produced using ______.
3. Brewer's yeast is scientifically known as ______.
4. Penicillin was discovered by ______.
5. Citric acid is produced by ______.
6. Streptokinase acts as a ______ buster.
7. Cyclosporin A is produced by ______.
8. Statins are produced by ______.
9. BOD stands for ______.
10. The major component of biogas is ______.
11. ______ are anaerobic microorganisms that produce methane.
12. Rhizobium helps in ______ fixation.

Answers: Lactobacillus, Propionibacterium shermanii, Saccharomyces cerevisiae, Alexander Fleming, Aspergillus niger, clot, Trichoderma polysporum, Monascus purpureus, Biochemical Oxygen Demand, methane, methanogens, nitrogen

17. Match the Following

Column A	Column B
1. Lactobacillus	a. Statins
2. Aspergillus niger	b. Curd
3. Monascus purpureus	c. Citric acid
4. Methanobacterium	d. Biogas
5. Rhizobium	e. Nitrogen fixation

Answers: 1-b, 2-c, 3-a, 4-d, 5-e

18. Assertion and Reason Practice

1. Assertion: Curd is formed due to the activity of lactic acid bacteria.
   Reason: LAB convert lactose into lactic acid.
   Answer: Both Assertion and Reason are correct, and the Reason correctly explains the Assertion.
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2. Assertion: BOD decreases during effective secondary sewage treatment.
   Reason: Microorganisms degrade organic matter present in sewage.
   Answer: Both Assertion and Reason are correct, and the Reason correctly explains the Assertion.
3. Assertion: Methanogens are important in biogas production.
   Reason: Methanogens produce methane under anaerobic conditions.
   Answer: Both Assertion and Reason are correct, and the Reason correctly explains the Assertion.
4. Assertion: Rhizobium is a biofertiliser.
   Reason: Rhizobium helps in biological nitrogen fixation.
   Answer: Both Assertion and Reason are correct, and the Reason correctly explains the Assertion.
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Quick Revision

Microbes → Food → Industry → Medicine → Sewage Treatment → Biogas → Biofertilisers