Microbes in Human Welfare

Microorganisms play a crucial role in various aspects of human life, including food production, medicine, industry, and environmental conservation. While some microbes cause diseases, many are beneficial and contribute to human welfare in multiple ways. This chapter explores the different roles of microbes in various fields.

Microbes in Household Products

1. Microbial Fermentation in Dairy Products

• Lactic Acid Bacteria (LAB) such as Lactobacillus help in the production of curd from milk.

• LAB improve nutritional quality and inhibit harmful microbes.

2. Fermentation in Bread and Beverages

• Yeast (Saccharomyces cerevisiae) is used for bread making, producing carbon dioxide that makes the dough rise.

• Yeast is also used in the fermentation of alcoholic beverages like beer and wine.

3. Microbes in Pickles and Other Fermented Foods

• Fermented foods like idli, dosa, and kimchi involve bacterial and fungal fermentation, improving flavor and digestibility.

Microbes in Industrial Production

1. Production of Antibiotics

• Antibiotics are substances produced by microbes to kill or inhibit other microbes.

• Example: Penicillin discovered by Alexander Fleming is derived from Penicillium fungus.

2. Microbes in Organic Acids and Enzymes

• Organic Acids: Aspergillus niger (citric acid), Acetobacter aceti (acetic acid), Clostridium butyricum (butyric acid).

• Enzymes: Streptococcus (streptokinase for clot removal), Aspergillus (pectinase for juice clarification), Lactobacillus (lactic acid production).

3. Production of Bioactive Molecules

• Cyclosporin A (an immunosuppressant) is obtained from Trichoderma polysporum.

• Statins (cholesterol-lowering drugs) are produced by Monascus purpureus.

Microbes in Sewage Treatment

1. Primary Treatment (Physical Removal of Solids)

• Large particles are removed through sedimentation and filtration.

2. Secondary Treatment (Biological Decomposition)

• Aerobic bacteria break down organic matter into carbon dioxide and sludge.

• Anaerobic bacteria in sludge digest the organic waste, producing biogas.

3. Tertiary Treatment (Chemical and Disinfection Treatment)

• Removal of harmful pathogens and chemicals before releasing the treated water into natural water bodies.

Microbes in Biogas Production

1. Role of Methanogens

• Methanogenic bacteria like Methanobacterium decompose organic matter to release methane (CH₄), carbon dioxide (CO₂), and hydrogen (H₂).

• Biogas is used as an eco-friendly fuel for cooking and electricity generation.

2. Biogas Plant Structure

• Digester: Chamber where anaerobic decomposition occurs.

• Gas Holder: Stores methane-rich biogas for usage.

Microbes in Agriculture

1. Biofertilizers (Nitrogen Fixation and Soil Health)

• Rhizobium in legume roots fixes atmospheric nitrogen into usable forms.

• Azotobacter and Azospirillum enhance soil nitrogen levels.

• Mycorrhiza (Fungi-Root Association) improves phosphorus absorption and plant resistance to pathogens.

2. Biopesticides (Eco-Friendly Pest Control)

• Bacillus thuringiensis (Bt) produces Bt toxin that kills insect larvae.

• Trichoderma fungi act against plant pathogens.

Microbes in Environmental Applications

1. Microbial Bioremediation

• Microbes help in cleaning up pollutants and toxic waste.

• Pseudomonas putida is used in oil spill cleanup.

2. Microbes in Composting and Waste Management

• Decomposers like bacteria and fungi break down organic waste into manure.

• Used in composting, vermicomposting, and solid waste management.

Importance of Microbes in Human Welfare

• Contribute to food production, industry, medicine, and environmental sustainability.

• Offer eco-friendly solutions like biopesticides, biofertilizers, and biogas.

• Used in biotechnology and genetic engineering for improving human health and agriculture.