Introduction to Microbes in Human Welfare

Microorganisms are tiny living organisms that play a crucial role in human welfare. They include bacteria, fungi, viruses, protozoa, and algae. Although some microbes cause diseases, many are beneficial and are extensively used in industries, medicine, agriculture, and environmental management. For NEET aspirants, the chapter Microbes in Human Welfare is a scoring topic from Class 12 Biology, based mainly on NCERT.

Direct Links to Download 2025-26 Biology Notes (PDF)

► Click “Download Now” next to your subject to access the free PDF.

♦ The Living World ⇒ Download Now

♦ Structural Organisation in Animals ⇒ Download Now

♦ Cell - The Unit of Life ⇒ Download Now

♦ Plant Physiology ⇒ Download Now

♦ Human Physiology ⇒ Download Now

♦ Reproduction in Organisms ⇒ Download Now

♦ Evolution ⇒ Download Now

♦ Microbes in Human Welfare ⇒ Download Now

♦ Biotechnology and its Applications ⇒ Download Now

♦ Ecology ⇒ Download Now

Microbes in Household Products

Microbes are widely used in the preparation of various household products.

1. Curd Formation:
Lactic acid bacteria (LAB) such as Lactobacillus convert milk into curd by fermenting lactose into lactic acid. LAB also improves the nutritional quality of curd by increasing vitamin B12.

2. Bread and Bakery Products:
Yeast (Saccharomyces cerevisiae) is used in baking to produce carbon dioxide, which helps in rising of dough.

3. Fermented Beverages:
Microbes are used in the preparation of alcoholic drinks like wine, beer, and toddy through fermentation.

Microbes in Food Production

Several food items are produced using microbes through fermentation.

Examples include:

• Cheese: Different microbes are used for cheese ripening and flavor.

• Yogurt: Produced by lactic acid fermentation.

• Idli and Dosa Batter: Fermented by bacteria and yeast.

Fermentation improves food digestibility, flavor, and nutritional value.

Microbes in Industrial Products

Microbes are used on an industrial scale to produce various useful products.

1. Antibiotics:
Antibiotics are substances produced by microbes that kill or inhibit the growth of other microorganisms.
Examples:

• Penicillin – produced by Penicillium

• Streptomycin – produced by Streptomyces

2. Organic Acids:

• Citric acid – produced by Aspergillus niger

• Acetic acid – produced by Acetobacter

3. Enzymes:
Microbial enzymes are used in detergents, food processing, and textiles.

Microbes in Sewage Treatment

Sewage treatment involves the removal of organic matter and harmful microorganisms from wastewater.

Primary Treatment:
Physical removal of large and small particles.

Secondary Treatment (Biological Treatment):
Microbes play a key role in breaking down organic matter. Activated sludge containing aerobic microbes is used.

Secondary treatment reduces Biochemical Oxygen Demand (BOD) significantly, making water safe for discharge.

Microbes in Biogas Production

Biogas is a mixture of gases like methane, carbon dioxide, and hydrogen, produced by microbial activity.

Methanogenic bacteria such as Methanobacterium are responsible for biogas production.
Biogas plants utilize cattle dung, sewage, and agricultural waste.

Benefits of biogas:

• Renewable energy source

• Reduces pollution

• Produces nutrient-rich manure

Microbes as Biocontrol Agents

Microbes are used as natural enemies to control pests without harming the environment.

Examples:

• Bacillus thuringiensis (Bt) used against insect pests

• Trichoderma used to control plant pathogens

Biocontrol methods reduce the use of chemical pesticides.

Microbes as Biofertilizers

Biofertilizers are microorganisms that enrich soil fertility by fixing atmospheric nitrogen or enhancing nutrient availability.

Examples:

• Rhizobium – nitrogen fixation in leguminous plants

• Azotobacter – free-living nitrogen fixer

• Cyanobacteria – improve soil fertility in paddy fields

Biofertilizers promote sustainable agriculture.

Importance of Microbes in Human Welfare for NEET

This chapter is important for NEET because:

• Most questions are direct from NCERT

• Examples and diagrams are frequently asked

• It is a highly scoring unit

Understanding applications and examples is the key to mastering this chapter.

Quick Summary Table

Conclusion

Microbes play an essential role in human welfare by contributing to food production, medicine, industry, agriculture, and environmental protection. Understanding their beneficial applications is vital for NEET aspirants. With clear concepts and NCERT-focused preparation, students can easily score full marks from this chapter. StudentBro.in provides well-structured, NEET-oriented Biology notes to support effective learning.