08-01-2013, 12:28 PM
Microbes in Human Welfare
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Microbes inHousehold Products
Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it to curd. LAB produce acids that coagulate and partially digest the milk proteins. It also improves its nutritional quality by increasing vitamin B12. In our stomach too, the LAB play very beneficial role in checking disease causing microbes.
The dosa and idli is also fermented by bacteria. The dough, which is used for making bread, is fermented using baker’s yeast (Saccharomyces cerevisiae). A number of traditional drinks and foods are also made by fermentation by the microbes. ‘Toddy’, a traditional drink of some parts of southern India is made by fermenting sap from palms.
Beverages
In industry, microbes are used to synthesize a number of products valuable to human beings. Beverages and antibiotics are some examples. Production on an industrial scale requires growing microbes in very large vessels called fermentors.
Microbes like yeast are used for the production of beverages like wine, beer, whisky, brandy or rum.
ANTIBIOTICS
Anti is a Greek word that means ‘against’, and bio means ‘life’, together they mean ‘against life’ (in thecontext of disease causing organisms); whereas with reference to human beings, they are ‘pro life’ and not against.
Antibiotics have greatly improved our capacity to treat deadly diseases such as plague, whooping cough (kali khansi), diphtheria (gal ghotu) and leprosy (kusht rog), which used to kill millions all over the globe. Today, we cannot imagine a world without antibiotics.
BIOACTIVE MOLECULES
Streptokinase produced by the bacterium Streptococcus and modified by genetic engineering is used as a ‘clot buster’ for removing clots from the blood vessels of patients who have undergone myocardial infarction leading to heart attack.
Cyclosporin A that is used as an immunosuppressive agent in organ-transplant patients is produced by the fungus Trichoderma polysporum.
STAGES OF SEWAGE TREATMENT
Primary treatment: steps of this treatment basically involve physical removal of particles – large and small – from the sewage through filtration and sedimentation. These are removed in stages; initially, floating debris is removed by sequential filtration. Then the grit (soil and small pebbles) are removed by sedimentation. All solids that settle form the primary sludge, and the supernatant forms the effluent. The effluent from the primary settling tank is taken for secondary treatment.
Secondary treatment or Biological treatment: The primary effluent is passed into large aeration tanks, where it is constantly agitated mechanically and air is pumped into it. This allows vigorous growth of useful aerobic microbes into flocs (masses of bacteria associated with fungal filaments to form mesh like structures). While growing, these microbes consume the major part of the organic matter in the effluent.
Biocontrol Agents
This is a holistic approach that seeks to develop an understanding of the webs of interaction between the myriad of organisms that constitute the field fauna and flora.
Baculoviruses (genus Nucleopolyhedro virus) are pathogens that attack insects and other arthropods. These viruses are excellent candidates for species-specific, narrow spectrum insecticidal applications.
An example of microbial Biocontrol agents that can be introduced in order to control butterfly caterpillars is the bacteria Bacillus thuringiensis (often written as Bt ). These are available in sachets as dried spores which are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees, where these are eaten by the insect larvae. In the gut of the larvae, the toxin is released and the larvae get killed.