Microbes in Human Welfare

Microbes are a crucial component of earth's biological systems and exist in a variety of environments, including extreme conditions. They include bacteria, fungi, protozoa, and viruses, among others, many of which are beneficial to human welfare.

8.1 Microbes in Household Products

• Curd Production: Conversion of milk to curd by lactic acid bacteria (LAB) like Lactobacillus, which increase nutritional value by enhancing vitamin B12.
• Fermentation in Foods:
  • Dosa and Idli: Fermented by bacteria producing carbon dioxide.
  • Bread: Fermented using baker's yeast (Saccharomyces cerevisiae).
  • Toddy: Fermented sap from palms.
  • Cheese: Different cheeses are characterized by specific microbial cultures.

8.2 Microbes in Industrial Products

• Fermented Beverages: Yeast (Saccharomyces cerevisiae) used in production of alcoholic drinks like wine, beer, whisky.
• Antibiotics:
  • Penicillin: Discovered by Alexander Fleming; effective against various diseases.
  • Other Antibiotics: Purified from other microbes.
• Chemical and Enzyme Production:
  • Organic Acids: Produced by fungi and bacteria (e.g., citric, acetic acids).
  • Enzymes: Lipases for detergent, pectinases for juice clarification.
  • Bioactive Molecules: Cyclosporin A as an immunosuppressant, Statins for cholesterol reduction.

8.3 Microbes in Sewage Treatment

• Sewage Treatment Process:
  • Primary Treatment: Removal of solids through filtration.
  • Secondary Treatment: Biological treatment using aerobic microbes to lower Biochemical Oxygen Demand (BOD).
  • Activated Sludge: Used in anaerobic digesters to produce biogas.
• Environmental Impact: Important for treating waste water and reducing pollution.

8.4 Microbes in Production of Biogas

• Biogas: Methane-rich gas produced by methanogens like Methanobacterium from cattle dung (gobar).
• Biogas Plants: Rural setup for using cattle excreta to produce biogas as fuel.

8.5 Microbes as Biocontrol Agents

• Biocontrol: Use of natural predators and pathogens to control pests and diseases.
• Examples:
  • Bacillus thuringiensis (Bt): Used against insect larvae.
  • Trichoderma: Fungi used against plant pathogens.
  • Baculoviruses: Specific to pest insects.

8.6 Microbes as Biofertilisers

• Biofertilisers: Organisms that enrich soil nutrients.
  • Nitrogen Fixing Bacteria: Rhizobium in legume nodules.
  • Free-living Bacteria: Azospirillum and Azotobacter enrich soil nitrogen.
  • Mycorrhiza: Fungal associations improving phosphorus uptake.
  • Cyanobacteria: Nitrogen-fixing in paddy fields.

Summary

• Microbes play significant roles across various sectors, from food production to industrial applications.
• They are essential in environmental management, particularly in sewage treatment and biogas production.
• Biocontrol and biofertiliser applications reduce reliance on chemical alternatives, promoting sustainable agriculture and environmental protection.