MICROBES IN HUMAN WELFARE
- Microbes are diverse – protozoa, bacteria, fungi and microscopic plants viruses, viroids and also prions (proteinocious infectious agents)
- Microbes like bacteria and fungi can be grown in nutrient media to form colonies and can be seen in naked eyes.
- Some microbes’ causes diseases and some are useful for human being.
MICROBES IN HOUSEHOLD PRODUCTS:
Lactic acid Bacteria:
- Lactic acid Bacteria (LAB) grow in milk and convert it to curd.
- LAB produces acids that coagulate and partially digest milk proteins.
- A small amount of curd added to fresh milk as inoculums or starter.
- LAB improves nutritional quality of milk by increasing vitamin B12
- LAB plays very important role in checking disease causing microbes.
- Dough, used to make dosa and idli is also fermented by bacteria.
- The puffed-up appearance of dough is due to the production of CO2.
- Baker’s yeast (Saccharomyces cervisiae) is used to making bread.
- ‘Toddy’ a traditional drink is made by fermentation of sap from palms.
- Large holes in ‘Swiss cheese’ are due to production of large amount of CO2 by a bacterium named Propionibacterium sharmanii.
- The ‘Roquefort cheese’ is ripened by specific fungi, which gives specific flavor.
MICROBES IN INDUSTRIAL PRODUCTS:
- Microbes are used in industry to synthesize a number of products
- Beverages and antibiotics are some examples.
- Microbes are grown in very large vessels called fomenters.
Fermented Beverages:
- Yeasts are used for production of beverages like wine, beer, whisky, brandy or rum.
- Saccharomyces cervisiae commonly called ‘brewer’s yeast used for fermenting malted cereals and fruit juices to produce ethanol.
- The type of raw material used for fermentation and the processing, different types of alcoholic drinks are produced.
- Wine and beer are produced without distillation.
- Whisky, brandy and rum are produced by distillation of the fermented brooth.
Antibiotics:
- Antibiotics are the chemical substances which are produced by some microbes and can kill or retard the growth of other microbes.
- The first antibiotic discovered is the penicillin, from a mould (fungus) Penicillium notatum.
- Antibiotics have greatly improved our capacity to treat deadly diseases such as plague, whooping cough. Diphtheria and leprosy.
Chemicals, Enzymes and other Bioactive Molecules:
- Aspegillus niger (a fungus) produces citric acid.
- Acetobacter aceti (a bacterium) produce acetic acid.
- Clostridium butylicum (a bacterium) produce butyric acid.
- Lactobacillus(a bacterium) produces lactic acid.
- Saccharomyces cerevisiae (yeast) used for production of ethanol.
- Lipases are used in detergent produced by microbes.
- Pectinase, proteases and cellulase, make bottled fruit juices clearer.
- Streptokinase produced by Streptococcus used as a ‘clot buster’, for removing clots from the blood vessels.
- Cyclosporin-A produced by a fungus called Trichoderma polysporum used as immunosuppressive agent in organ transplantation.
- Statins produced by Monascus purpureus used as blood cholesterol lowering agents. It acts as competitive inhibitor for the enzyme responsible for synthesis of cholesterol.
MICROBES IN SEWAGE TREATMENT:
- The waste water generated in cities and town containing human excreta. This municipal water-water is called sewage.
- Before disposal to the natural body sewage is treated in sewage treatment plants (STPs) to make it less polluting.
- Treatment is done by heterotrophic microbes naturally present in sewage.
Primary treatment:
- Involves the physical removal of particles – large and small from sewage through filtration and sedimentation.
- Initially floating debris is removed by sequential filtration.
- The grit (soil and small pebbles) are removed by sedimentation.
- All solids that settle form the primary sludge, and the supernatant forms the effluents.
- The effluents are from the primary settling tank taken for secondary treatment.
CBSE Biology (Chapter Wise) Class XII ( By Mr. Hare Krushna Giri )
Email Id : [email protected]
