Microbes in Human Welfare – NEET NOTES

Introduction

Microorganisms, or microbes, are tiny living entities that include bacteria, fungi, viruses, protozoa, and algae. Though often associated with diseases, microbes play an indispensable role in human welfare. Their remarkable ability to perform fermentation, decomposition, and biosynthesis makes them vital in industries, medicine, agriculture, and environmental management.

Microbes are employed in the production of antibiotics, enzymes, vaccines, biofertilizers, biopesticides, and biofuels. They are also essential in processes like waste management, genetic engineering, and bioremediation. Their contribution is not only limited to industrial and medical applications but also extends to our daily lives, including food processing, beverage production, and waste treatment.

In this detailed note, we will explore the applications of microbes in human welfare, categorized into the following sections:

  • Microbes in household products.
  • Microbes in industrial production.
  • Microbes in agriculture.
  • Microbes in medicine.
  • Microbes in environmental management.
  • Microbes in biotechnology.

Types of Microorganisms in Human Welfare

Microbes involved in human welfare include:

  1. Bacteria
  • Single-celled prokaryotic organisms.
  • Found in soil, water, air, and inside living organisms.
  • Used in fermentation, nitrogen fixation, and antibiotic production.
  1. Fungi
  • Eukaryotic, heterotrophic organisms.
  • Decomposers and producers of antibiotics and enzymes.
  1. Protozoa
  • Unicellular eukaryotic organisms.
  • Used in biological research and sewage treatment.
  1. Viruses
  • Acellular entities containing either DNA or RNA.
  • Used in genetic engineering, vaccine production, and gene therapy.
  1. Algae
  • Photosynthetic organisms, mainly aquatic.
  • Used in biofuel production and wastewater treatment.

Microbes in Household Products

1. Microbes in Curd Formation

  • Lactic acid bacteria (LAB), including:
  • Lactobacillus acidophilus.
  • Streptococcus thermophilus.
  • These microbes convert lactose (milk sugar) into lactic acid, which coagulates milk proteins, forming curd.
  • Nutritional benefits:
  • Curd is rich in vitamin B12.
  • Improves digestion and gut health.
  • Prevents the growth of harmful bacteria in the gut.
  • Enhances immunity.

2. Microbes in Bread Making

  • Saccharomyces cerevisiae (baker’s yeast) is used to ferment bread dough.
  • During fermentation:
  • Sugars → Ethanol + CO₂.
  • The release of CO₂ makes the dough rise.
  • The bread becomes soft and spongy due to the trapped CO₂ bubbles.
  • Industrial significance:
  • Large-scale bread production relies on yeast fermentation.

3. Microbes in Alcoholic Beverages

  • Alcoholic beverages such as beer, wine, and whisky are produced by the fermentation of carbohydrates by yeast.
  • Saccharomyces cerevisiae ferments glucose into:
  • Ethanol + CO₂.
  • Different beverages and their raw materials:
  • Beer → Malted barley.
  • Wine → Grapes.
  • Whisky → Grains.
  • Alcohol content varies with fermentation time and conditions.

Microbes in Industrial Production

Microbes play a significant role in large-scale industrial production of antibiotics, organic acids, enzymes, biofuels, and chemicals.

1. Antibiotic Production

  • Antibiotics are substances produced by microbes that inhibit or kill other microbes.
  • Common antibiotics and their microbial sources:
  • Penicillin – Produced by Penicillium notatum.
  • Streptomycin – Derived from Streptomyces griseus.
  • Chloramphenicol – Produced by Streptomyces venezuelae.
  • Erythromycin – From Saccharopolyspora erythraea.
  • Applications of antibiotics:
  • Treating bacterial infections.
  • Preventing bacterial growth in wounds.
  • Used in veterinary medicine and agriculture.

2. Enzyme Production

  • Microbial enzymes have wide industrial applications.
  • Examples:
  • Lipase: Used in detergents and dairy products.
  • Amylase: Converts starch into sugar syrups in the food industry.
  • Pectinase: Clarifies fruit juices.
  • Protease: Used in detergents and leather processing.

3. Organic Acid Production

  • Aspergillus niger produces citric acid used in food preservation.
  • Lactic acid is produced by Lactobacillus species.
  • Acetic acid is produced by Acetobacter aceti, used in vinegar production.

4. Biofuel Production

  • Methanogenic bacteria, such as Methanobacterium, are used in biogas production.
  • Biogas composition:
  • Methane (CH₄): 50-75%.
  • Carbon dioxide (CO₂): 25-50%.
  • Biogas applications:
  • Renewable energy source.
  • Reduces waste.
  • Environmentally friendly alternative to fossil fuels.

Microbes in Agriculture

Microbes are beneficial in agriculture as biofertilizers and biopesticides, promoting plant growth and controlling pests.

1. Microbes as Biofertilizers

  • Biofertilizers are live microbes that improve soil fertility.
  • Types of biofertilizers:
  • Nitrogen-fixing bacteria:
    • Rhizobium: Symbiotic bacteria in legume root nodules.
    • Azotobacter: Free-living nitrogen-fixing bacteria.
  • Cyanobacteria:
    • Anabaena and Nostoc fix atmospheric nitrogen.
  • Phosphate-solubilizing bacteria:
    • Pseudomonas and Bacillus solubilize insoluble phosphates.

2. Microbes as Biopesticides

  • Biopesticides are microbial agents used to control pests.
  • Examples:
  • Bacillus thuringiensis (Bt):
    • Produces insecticidal proteins.
    • Used in Bt cotton and Bt brinjal.
  • Trichoderma:
    • Fungal biocontrol agent against plant pathogens.
  • Nucleopolyhedrovirus (NPV):
    • Used to control caterpillar pests in crops.

Microbes in Medicine

Microbes are extensively used in the production of antibiotics, vaccines, and therapeutic agents.

1. Antibiotics

  • Antibiotics are substances produced by microbes that inhibit the growth of other microbes.
  • Examples:
  • Penicillin: Treats bacterial infections.
  • Tetracycline: Broad-spectrum antibiotic.
  • Rifampicin: Used to treat tuberculosis.

2. Vaccines

  • Vaccines contain weakened or inactivated pathogens.
  • They stimulate the immune system to produce antibodies.
  • Microbes used in vaccines:
  • BCG vaccine: Contains Mycobacterium bovis.
  • Polio vaccine: Contains inactivated poliovirus.
  • Hepatitis B vaccine: Produced using recombinant DNA technology.

3. Gene Therapy

  • Microbes are used in gene therapy to deliver healthy genes into human cells.
  • Adenoviruses and retroviruses are used as vectors.
  • Applications of gene therapy:
  • Treating genetic disorders like cystic fibrosis.
  • Treating certain cancers.

Microbes in Environmental Management

Microbes are used in bioremediation, sewage treatment, and waste management.

1. Sewage Treatment

  • Sewage treatment involves biological degradation by microbes.
  • Primary treatment:
  • Physical removal of large particles.
  • Secondary treatment:
  • Aerobic bacteria decompose organic matter.
  • Tertiary treatment:
  • Removes remaining nutrients.

2. Bioremediation

  • Bioremediation uses microbes to clean up pollutants.
  • Examples:
  • Pseudomonas putida: Degrades petroleum hydrocarbons.
  • Alcanivorax borkumensis: Cleans oil spills.

Conclusion

Microbes are essential for human welfare, contributing to food production, medicine, industry, agriculture, and environmental management. Their role in biotechnology and genetic engineering continues to expand, offering sustainable solutions to various challenges. Understanding microbial applications is crucial for NEET preparation as it frequently appears in the exam.

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