MICROBES IN HUMAN WELFARE
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.
· 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 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.
· 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.
Secondary treatment or Biological treatment:
· The primary effluent is passed into large aeration tanks.
· This allows vigorous growth of useful aerobic microbes into flocs.
· The growth of microbes consumes the major part of the organic matter in the effluent. This significantly reduces the BOD (biochemical oxygen demand) of the effluent.
· BOD refers to the amount of oxygen required to oxidize total organic matter by bacteria, present in one liter of water.
· BOD is the measures of the organic matter present in the water.
· Greater the BOD of the waste water more is its polluting potential.
· Once the BOD of sewage reduced significantly, the effluent is then passed into the settling tank where the bacterial ’flocs’ are allowed to sediment. This sediment is called activated sludge.
· Small part of activated sludge is pumped back to aeration tank to serve as the inoculums.
· The remaining sludge is pumped into anaerobic sludge digester.
· In the anaerobic sludge digester there is other kinds of bacteria which grow anaerobically, digest the bacteria and fungi in the sludge.
· During this digestion bacteria produce biogas, (mixture of methane, hydrogen sulphide and carbon dioxide)
· The effluent from the secondary treatment plant is released into natural water body like rivers and streams.
· Ganga Action Plan and Yamuna Action Plan initiated by Ministry of Environment and Forest to save these major rivers of our country.
· It is proposed to build a large number of sewage treatment plants so that only treated sewage may be discharged into the rivers.
MICROBES IN PRODUCTION OF BIOGAS:
· Biogas is a mixture of gases (predominantly methane) produced by the microbial activity and is used as fuel.
· Certain bacteria grow anaerobically on cellulosic material, produce large amount of methane along with CO2 and H2S. These bacteria are collectively called methanogens. One common bacterium is Methanobacterium.
· These bacteria present in the rumen of cattle, plays essential role in nutrition of cattle by digesting cellulose. Hence the excreta (dung) used for the production of biogas.
MICROBES AS BIOCONTROL AGENT:
· Biocontrol refers to the use of biological methods for controlling plant diseases and pests.
· Effect of use of chemical, insecticide and pesticide to control disease and pests:
o These chemicals are toxic and extremely harmful to human beings and animals
o Polluting our environment (soil, ground water), fruits, and vegetables.
o Soil is polluted through use of weedicides to remove weeds.
Biological control of pest and disease:
· Use of biocontrol measures will greatly reduce our dependence on toxic chemical and pesticides.
· The Ladybird and Dragonflies are used to get rid of aphids and mosquitoes.
· Bacillus thuringiensis (Bt) used to control butterfly caterpillars.
· Dried spores are mixed with water and sprayed onto vulnerable plants, where these are eaten by the insect larvae.
· In the gut of the larvae, the toxin is released and the larvae get killed.
· Trichodermaa free living fungus used to control several plant pathogens.
· Baculoviruses are pathogen that attack insects and other arthropods
· The majority of baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus.
· These viruses are excellent candidates for species-specific, narrow spectrum insecticidal application.
· They have no negative impacts on plants, mammals, birds, fish, etc.
· This is very use full in integrated pest managements (IPM).
MICROBES AS BIOFERTILIZERS:
· Biofertilizers are organisms that enrich the nutrient quality of the soil.
· Main biofertilizers are the bacteria, fungi and cyanobacteria.
· Rhizobium form root nodules in legumes and fix atmospheric nitrogen.
· Azospirilium and Azotobacter free living bacteria fix atmospheric nitrogen and thus increasing nitrogen content of the soil.
· Mycorrhiza: fungi symbiotically associated with root of plants.
· Many members of the genus Glomus form Mycorrhiza.
o Provide phosphorus to the plants from the soil.
o Make the plant resistant to root-borne pathogen.
o Increase tolerance to salinity and drought.
· Cyanobacteria like Anabaena, Nostoc, and Oscillatoria etc:
o Fix atmospheric nitrogen.
o add organic matter to the soil and
o Increase soil fertility.
§ DO : Dissolved Oxygen
§ GAP : Ganga Action Plan
§ KVIC : Khadi and Village Industries Commission
§ TMV : Tobacco Mosaic Virus
§ YAP : Yamuna Action Plan
§ IPM: Integrated Pest Management.