Microbes in Human Welfare Notes

Key Concepts about Microbes in Human Welfare

Microbes in Household Products

  • Curd Formation:

    • Lactobacillus bacteria coagulate milk proteins to form curd.

    • Increases Vitamin B12 content in curd.

    • Helps to check the growth of harmful microbes in the gut.

  • Cheese Formation:

    • The texture and taste of cheese depend on the type of microbe used.

    • Examples:

      • Roquefort cheese (fungi)

      • Swiss cheese (bacteria: Propionibacterium sharmanii)

  • Dough Formation:

  • Essential for making idli, dosa, and bread dough.

    • Bread dough -Utilizes yeast (Saccharomyces cerevisiae, also known as Baker's yeast).

    • idli, dosa - Fermented by Bacteria.

  • Other Uses:

    • Toddy: A traditional South Indian drink made by fermenting sap from plants.

    • Fermentation of fish, soybean, and bamboo for food.

Microbes in Production of Acids

  • Key Bacteria and Acids:

    • Lactobacillus (Bacterium) - Lactic Acid

    • Clostridium butylicum (Bacterium) - Butyric Acid

    • Acetobacter aceti (Bacterium)- Acetic Acid

    • Aspergillus niger (Fungi)- Citric Acid


Microbes in Production of Fermented Beverages

  • Brewer's Yeast:

    • Yeast -Saccharomyces cerevisiaeis used in fermenting alchol.

    • Different alcoholic drinks depend on raw materials used and processing type (e.g., distillation).

    • Drinks produced by distillation: Whiskey, Brandy, Rum.

    • Drinks produced without distillation: Wine, Beer.

Microbes in Production of Enzymes

  • Enzymes Functions:

    • Specific molecules speeding up biochemical reactions.

    • Lipases: Used in detergents for removing oily stains.

    • Protease and Pectinase: Clear fruit juices.





Microbes in Production of Bioactive Molecules

  • Streptococcus bacteria:

    • Streptokinase: Acts as a 'clot buster' for heart attack patients by removing blood clots.

  • Yeast:

    • Monascus purpureus: Produces Statins that lower blood cholesterol.

  • Fungi:

    • Trichoderma polysporum: Produces Cyclosporin A, an immunosuppressive agent.

Microbes in Production of Antibiotics

  • Antibiotics:

    • Chemical substances produced by microbes to kill or inhibit the growth of disease-causing microbes.

    • Discovery: Alexander Fleming discovered penicillin from
      Penicillium notatum.

    • Full potential established later by Ernest Chain and Howard Florey.

    • Nobel Prize awarded to Fleming , Chain And Florey in 1945 for this discovery.


Microbes in Production of Biogas

  • Biogas Composition:

    • Consists of methane, carbon dioxide, and hydrogen gas.

    • Produced by methanogens (e.g., Methanobacterium) feeding anaerobically on cellulose.

    • Methanogens found in the rumen of cattle and in cow dung.

  • Biogas Plant Components:

    • Gas-holder and sludge digester are key components of a typical biogas plant.

    • Technology developed in India by IARI( Indian Agricultural Research Institute and KVIC ( Khadi and Village Industries Commission)

Microbes in Sewage Treatment

  • Sewage Treatment Stages:

    1. Primary Treatment:( Physical) Physical removal of particles via filtration and sedimentation resulting in primary sludge and effluent.

    2. Secondary Treatment:( Biological) Involves aeration tanks where Flocs (Masses of bacteria associated with fungal filaments ) consume organic matter, leading to reduced BOD.

      • In the settling tank Bacterial flocs which sediment are called activated sludge and effluent left above is called secondary effluent which is drained into water bodies.

      • Anaerobic digesters break down activated sludge producing biogas.

Microbes as Biofertilizers

  • Biofertilizers: Organisms that enrich soil quality (e.g., cyanobacteria, eubacteria, fungi).

    • Eubacteria: Nitrogen fixation associated with legumes - Rhizobium
      Free living Nitrogen fixing Bacertia - Azospirillum, Azotobacter.

    • Cyanobacteria: Nitrogen fixation (e.g., Nostoc, Anabaena, oscillatoria).

    • Fungi: Form mycorrhizal associations with plant roots enhancing phosphorus uptake and providing resistance to pathogens.


Microbes as Biocontrol Agents

  • Fungi:

    • Trichoderma species: Aids in biocontrol in root ecosystems.

  • Bacteria:

    • Bacillus thuringiensis: Targets butterfly caterpillars by releasing toxins which get activated by alkaline ph. in caterpillars gut .

  • Virus:

    • Baculovirus: Used for narrow-spectrum insecticidal applications.