CBSE Class 12 Biology Microbes in Human Welfare Flow Chart

This Class 12 Biology flow chart notes page on Microbes in Human Welfare covers the microbes used in households, fermented beverages, the production of chemicals and antibiotics, microbes used to control pests and diseases, biogas production, biofertilisers, and sewage treatment.

Topics Covered

1. Microbes in Household Products
2. Fermented Beverages
3. Microbial Chemicals
4. Antibiotics
5. Microbes to Control Pests and Diseases
6. Production of Biogas
7. Microbes as Biofertilisers
8. Microbes in Sewage Treatment

1. Microbes in Household Products

1. Lactobacillus (LAB) grows in milk and converts it into curd. It produces lactic acid.
2. Baker's yeast (Saccharomyces cerevisiae) causes fermentation and produces carbon dioxide, which makes dough rise.
3. Toddy is a traditional drink prepared by fermenting palm sap.
4. Swiss cheese has holes made by the large amounts of carbon dioxide produced by Propionibacterium sharmanii.
5. Roquefort cheese is made with the help of fungi.

2. Fermented Beverages

Yeast ferments malted cereals and fruit juices to produce ethanol.
(i) With distillation: whisky, brandy and rum.
(ii) Without distillation: wine and beer.

3. Microbial Chemicals

1. Citric acid is produced by Aspergillus niger.
2. Acetic acid is produced by Acetobacter aceti.
3. Butyric acid is produced by Clostridium butyricum.
4. Lactic acid is produced by Lactobacillus.
5. Lipases are used in detergent formulations to remove oil stains.
6. Streptokinase is produced by Streptococcus. It is used as a clot buster, for removing clots from blood vessels.
7. Cyclosporin A is an immunosuppressive agent, used in organ transplants. It is produced by Trichoderma polysporum.
8. Statins are produced by Monascus purpureus. They lower blood cholesterol.

4. Antibiotics

Penicillin is an antibiotic produced by Penicillium notatum.

5. Microbes to Control Pests and Diseases

1. Bacillus thuringiensis produces a protein which kills caterpillars. It is used as a biopesticide.
2. Trichoderma, a fungus, kills root-borne pathogens.
3. Baculovirus (Nucleopolyhedrovirus) attacks specific insects and other arthropods.
4. Biological control uses natural predators. For example, the lady bird beetle is used to get rid of aphids, and dragonflies are used to eradicate mosquitoes.

6. Production of Biogas

Methanogens, such as Methanobacterium, act on cellular material to produce methane. They are found in anaerobic sludge digesters, in the rumen of cattle, in flooded rice fields and in cattle dung.

7. Microbes as Biofertilisers

Bacteria
(i) Symbiotic bacteria: Rhizobium.
(ii) Free living bacteria: Azospirillum and Azotobacter. Both fix atmospheric nitrogen and enrich the soil with nutrients.

Cyanobacteria
Anabaena, Nostoc and Oscillatoria enrich the organic matter of the soil through photosynthesis.

Fungi
Glomus fungi form associations with the roots of higher plants. They absorb phosphorus and give it to the plant. They also give the plant resistance to root-borne pathogens.

8. Microbes in Sewage Treatment

Primary Treatment
1. Filtration
2. Sedimentation

Secondary Treatment
1. Aerobic digestion
2. Anaerobic digestion, in which the sludge digesters produce biogas