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CHAPTER 10 – MICROBES IN HUMAN WELFARE, The organisms which are microscopic , i.e , can be seen only under microscope are called microbes., Microbes are present everywhere – in soil, water, bodies of animals and even in places where no other life-forms exist like in areas with temperature 100°C or - 50°C., Viruses, Viroids, bacteria, fungi, protozoans and certain algae are the diverse microbes., Some microbes like bacteria and fungi can be cultured on nutritive media to form colonies in laboratory., A large number of diseases are caused by microbes but they are also useful to mankind in many ways.
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SOME OF THE MOST IMPORTANT CONTRIBUTIONS OF MICROBES IN HUMAN WELFARE ARE GIVEN BELOW:-, Microbes in Household Products., Microbes in Industrial Products., Microbes in Sewage Treatment., Microbes in Production of Biogas., Microbes as Biocontrol Agents., Microbes as Biofertilizers.
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USES OF MICROBES IN HOUSEHOLD PRODUCTS:-, Lactobacillus and other Lactic Acid Bacteria (LAB), which grow on milk cause the formation of curd., Certain acids are produced by LAB which cause the coagulation and partial digestion of milk protein., Nutritional quality of milk is also increased by LAB by increasing the content of vitamin B₁₂., The LAB play very important role in checking disease causing microbes in the stomach.
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The fermentation of dough used for making idli and dosa is caused by bacteria and its puffed up appearance is due to the CO₂ produced during fermentation., Saccharomyces cerevisiae commonly called bakers yeast causes the fermentation of dough used for making bread., Toddy is produced by fermentation of sap from palms., Microbes are used in production of food items to ferment fish, bamboo shoots and soyabeans., There is difference in texture, flavour and taste of cheese depending upon the microbe used for fermentation and/or ripening., ‘Swiss cheese’ has large holes due to production of large amount of CO₂ by the bacterium Propionibacterium sharmanii., a specific fungus is used for the ripening of ‘Roquefort cheese’.
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USES OF MICROBES IN INDUSTRIAL PRODUCTS:-, The fermentative activity of microbes is used industrially to obtain a number of products namely:, Beverages., Antibiotics., Organic acids., Enzymes., Bioactive molecules.
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(1) BEVERAGES (ALCOHOLIC FERMENTATION):-, Fermentation of fruit juices and malted cereals into ethanol is done by yeast (Saccharomyces cerevisiae) which is commonly called brewer’s yeast., Depending upon the raw material used and the nature of processing, various alcoholic drinks are produced., With distillation – Whisky, Rum and Brandy., Without distillation – Wine and Beer.
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(2) ANTIBIOTICS:-, The term antibiotic is derived from the Greek words ‘anti’ – against and ‘bios’ – life and literally means against life (with reference to disease causing organisms)., The first antibiotic was penicillin which was discovered by Alexander Fleming while working on the bacteria Staphylococcus aureus but Ernst Chain and Howard Florey established its potential as an effective antibiotic., The Nobel prize in 1945 for this discovery was shared by all three of them., Penicillin is obtained from the fungus (a mould) Penicillium notatum., Antibiotics are used for the treatment of a number of diseases like diptheria, leprosy, pertusis (whooping cough), plague etc.
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(4) ENZYMES:-, The enzymes produced with the help of microbes are-, Lipases, Proteases, Pectinase, Lipases are lipid dissolving enzymes obtained from Candica lipolytica. Lipases are added in detergents for removing oily stains from laundry., Pectinases and Proteases are used to clear the fruit juices during bottling., Streptokinase is produced by Streptococcus. It is modified by genetic engineering and used as ‘Clot buster’ for dissolving the blood clots from the blood vessels of patients after myocardial infarction.
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(5) BIOACTIVE MOLECULES:-, Cyclosporin A-, A fungus Trichoderma polysporum produces it., It has immuno suppressive properties so it is used as an immuno suppressive agent during organ transplantation., Statins-, These are the products of fermentation activity of yeast, Monascus purpureus., It inhibits cholesterol synthesis, so used for lowering the blood cholesterol level.
