Biology and Human Welfare - Microbes in Human Welfare

Microbes in Household Products: $\textit{Lactobacillus}$ (LAB) converts milk to curd by producing lactic acid, which coagulates and partially digests milk proteins, increasing Vitamin $B_{12}$ content.

Industrial Fermentation: $\textit{Saccharomyces cerevisiae}$ (Brewer's yeast) is used for fermenting malted cereals and fruit juices to produce ethanol ($C_2H_5OH$).

Antibiotics: Penicillin, the first antibiotic, was discovered by Alexander Fleming from the mold $\textit{Penicillium notatum}$.

Chemicals and Enzymes: Microbes produce organic acids like Citric acid ($\textit{Aspergillus niger}$), Acetic acid ($\textit{Acetobacter aceti}$), and Butyric acid ($\textit{Clostridium butylicum}$). Enzymes like Lipases are used in detergents, and Streptokinase (from $\textit{Streptococcus}$) acts as a clot buster for myocardial infarction patients.

Sewage Treatment: Primary treatment is physical removal of particles. Secondary treatment is biological, involving 'flocs' (masses of bacteria and fungal filaments). The efficiency is measured by Biochemical Oxygen Demand ($BOD$).

Biogas Production: Produced by anaerobic breakdown of organic matter by methanogens such as $\textit{Methanobacterium}$. The gas contains mainly $CH_4$, $CO_2$, and $H_2$.

Biocontrol Agents: Use of biological methods like $\textit{Bacillus thuringiensis}$ ($Bt$) to control butterfly caterpillars and $\textit{Trichoderma}$ species to control several plant pathogens.

Biofertilisers: Organisms that enrich the nutrient quality of soil, including $\textit{Rhizobium}$ (symbiotic $N_2$ fixation), $\textit{Azotobacter}$ (free-living), and $\textit{Glomus}$ (fungi forming Mycorrhiza to absorb phosphorus).