Useful and Harmful Microbes — Maharashtra (SSC) Class 9 Science Solutions (Free)

Microbes are microscopic organisms invisible to the naked eye. Four main types are: (1) Bacteria - unicellular, prokaryotic organisms, (2) Viruses - non-living infectious agents, (3) Fungi - eukaryotic organisms like yeasts and molds, (4) Protozoa - single-celled eukaryotes. Microbes are found everywhere in nature.

Useful microbes include: (1) Lactobacillus in yogurt production improving digestion, (2) Yeast in bread and beer fermentation, (3) Rhizobium bacteria fixing nitrogen in soil for plant growth, (4) Streptomyces producing antibiotics like streptomycin, (5) Aspergillus in soy sauce and cheese production. These microbes benefit human health and industry.

Five harmful microbe diseases: (1) Tuberculosis - caused by Mycobacterium tuberculosis (bacteria), (2) Measles - caused by measles virus, (3) Malaria - caused by Plasmodium protozoan, (4) Cholera - caused by Vibrio cholerae bacteria, (5) Candidiasis - caused by Candida fungus. These pathogens cause serious health problems.

Beneficial gut bacteria (like E. coli and Lactobacillus) help by: (1) producing vitamin K and B vitamins essential for health, (2) breaking down complex carbohydrates we cannot digest alone, (3) producing short-chain fatty acids that nourish intestinal cells, (4) preventing harmful bacteria from establishing infection, (5) strengthening our immune system. A balanced gut microbiome is crucial for health.

Microbes are used in wastewater treatment through aerobic and anaerobic processes where bacteria break down organic matter and nutrients, purifying water for safe discharge or reuse. In bioremediation, specific bacteria and fungi degrade pollutants, heavy metals, and toxic substances from contaminated soil and water. This natural process is cost-effective and environmentally friendly.