Mnemonics: Microbes in Human Welfare | Biology Class 12 - NEET PDF Download

1. Microbes in Household Products

Concepts: Lactic acid bacteria (LAB, e.g., Lactobacillus) for curd; bacteria for dosa/idli dough fermentation (CO₂ production); Saccharomyces cerevisiae (baker’s yeast) for bread; microbes for toddy, fish, soybean, bamboo-shoot fermentation; Propionibacterium sharmanii for Swiss cheese (CO₂ holes); fungi for Roquefort cheese flavor.
Mnemonic: "Lacto Curds, Yeast Breads, Prop Swiss, Fungi Roq"
Breakdown:

• Lacto → Lactobacillus (LAB) converts milk to curd, producing acids and vitamin B12.

• Curds → Curd formation via LAB coagulation of milk proteins.

• Yeast → Saccharomyces cerevisiae ferments bread dough, producing CO₂ for puffing.

• Breads → Bread, dosa, idli dough rely on microbial fermentation (CO₂ via glycolysis).

• Prop → Propionibacterium sharmanii produces CO₂ for large holes in Swiss cheese.

• Swiss → Swiss cheese’s texture from Propionibacterium.

• Fungi → Specific fungi ripen Roquefort cheese for its flavor.

• Roq → Roquefort cheese’s unique taste.

2. Microbes in Industrial Products

Concepts: Saccharomyces cerevisiae for ethanol (beverages); Penicillium notatum for penicillin; Aspergillus niger for citric acid; Acetobacter aceti for acetic acid; Clostridium butylicum for butyric acid; Lactobacillus for lactic acid; Streptococcus for streptokinase; Trichoderma polysporum for cyclosporin A; Monascus purpureus for statins; microbes for lipases, pectinases, proteases.
Mnemonic : "Sacc Brews, Pen Blocks, Asper Citric, Aceto Vinegar, Clost Butyric, Lacto Lactic, Strep Clots, Trich Immune, Mona Statins"
Breakdown:

• Sacc Brews → Saccharomyces cerevisiae ferments cereals/fruit juices to produce ethanol for beverages.

• Pen Blocks → Penicillium notatum produces penicillin, blocking disease-causing microbes.

• Asper Citric → Aspergillus niger produces citric acid for food/industry.

• Aceto Vinegar → Acetobacter aceti produces acetic acid for vinegar.

• Clost Butyric → Clostridium butylicum produces butyric acid for chemical industries.

• Lacto Lactic → Lactobacillus produces lactic acid for food/pharmaceuticals.

• Strep Clots → Streptococcus produces streptokinase, a clot buster for heart patients.

• Trich Immune → Trichoderma polysporum produces cyclosporin A, an immunosuppressant.

• Mona Statins → Monascus purpureus produces statins, cholesterol-lowering agents.

3. Microbes in Sewage Treatment

Concepts: Heterotrophic microbes for primary (filtration, sedimentation) and secondary (aerobic flocs, anaerobic sludge digestion) treatment; flocs reduce BOD; anaerobic bacteria (e.g., Methanobacterium) produce biogas (methane, CO₂, H₂S).
Mnemonic: "Flocs Clean, Sludge Gas Pops"
Breakdown:

• Flocs → Aerobic microbes form flocs (bacteria + fungal filaments) in aeration tanks.

• Clean → Flocs consume organic matter, reducing BOD (biochemical oxygen demand).

• Sludge → Activated sludge settles; anaerobic bacteria digest it.

• Gas → Anaerobic bacteria (e.g., Methanobacterium) produce biogas (methane, CO₂, H₂S).

• Pops → Biogas is inflammable, used as energy.

4. Microbes in Biogas Production

Concepts: Methanogens (e.g., Methanobacterium) produce biogas (methane, CO₂, H₂) from cellulosic material (cattle dung); used in rural biogas plants for cooking/lighting.
Mnemonic: "Methano Dung Sparks Gas"
Breakdown:

• Methano → Methanobacterium (methanogens) anaerobically digest cellulose.

• Dung → Cattle dung (gobar) provides cellulosic material.

• Sparks → Biogas (methane-rich) is produced in biogas plants.

• Gas → Methane, CO₂, H₂ form inflammable biogas for fuel.

5. Microbes as Biocontrol Agents

Concepts: Bacillus thuringiensis (Bt) for butterfly caterpillars; Trichoderma for plant pathogens; Nucleopolyhedrovirus (baculoviruses) for insect pests; Ladybird for aphids; Dragonflies for mosquitoes.
Mnemonic: "Bt Zaps, Tricho Fights, Virus Bugs Lady"
Breakdown:

• Bt → Bacillus thuringiensis (Bt) kills butterfly caterpillars via toxin (used in Bt-cotton).

• Zaps → Bt toxin, sprayed or genetically engineered, targets insect larvae.

• Tricho → Trichoderma (fungus) controls plant pathogens in roots.

• Fights → Trichoderma acts as a biocontrol agent.

• Virus → Nucleopolyhedrovirus (baculoviruses) kills insects (species-specific).

• Bugs → Baculoviruses target arthropod pests, sparing non-target species.

• Lady → Ladybird beetles control aphids; Dragonflies control mosquitoes.

6. Microbes as Biofertilizers

Concepts: Rhizobium (symbiotic nitrogen fixation); Azospirillum, Azotobacter (free-living nitrogen fixation); Glomus (mycorrhiza, phosphorus uptake); Anabaena, Nostoc, Oscillatoria (cyanobacteria, nitrogen fixation in paddy fields).
Mnemonic: "Rhizo Roots, Cyano Pads, Fungi Feed"
Breakdown:

• Rhizo → Rhizobium fixes nitrogen in leguminous root nodules.

• Roots → Symbiotic bacteria enrich soil with organic nitrogen.

• Cyano → Cyanobacteria (Anabaena, Nostoc, Oscillatoria) fix nitrogen in paddy fields.

• Pads → Cyanobacteria add organic matter to rice fields.

• Fungi → Glomus (mycorrhiza) absorbs phosphorus for plants.

• Feed → Mycorrhiza boosts plant growth, resistance to pathogens.