Microbes in Human Welfare 1 Flashcards
Microbes like bacteria and many fungi can be grown
on nutritive media to form colonies (Figure 8.3), that can
be seen with the naked eyes. Such cultures are useful in
studies on micro-organisms
Lactobacillus- curd
Micro-organisms such as Lactobacillus and others
commonly called lactic acid bacteria (LAB) grow in milk and convert it
to curd. During growth, the LAB produce acids that coagulate and
partially digest the milk proteins. A small amount of curd added to the
fresh milk as inoculum or starter contain millions of LAB, which at
suitable temperatures multiply, thus converting milk to curd, which
also improves its nutritional quality by increasing vitamin B12. In our
stomach too, the LAB play very beneficial role in checking diseasecausing microbes.
fermentation- dough, bread,beer
The dough, which is used for making foods such as dosa and idli is
also fermented by bacteria. The puffed-up appearance of dough is due to
the production of CO2
gas.
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.
Microbes are also used to ferment fish, soyabean and bambooshoots to make foods.
cheese
Cheese, is one of the oldest food items in which
microbes were used. Different varieties of cheese are known by their
characteristic texture, flavour and taste, the specificity coming from the
microbes used.
For example, the large holes in ‘Swiss cheese’ are due to production of a large amount of CO2
by a bacterium named
Propionibacterium sharmanii. It is a hard cheese.
The ‘Roquefort cheese’ are ripened by
growing a specific fungi on them, which gives them a particular flavour.(Penicillium roqueforti (fungi)). it is a semi hard cheese
Fermented Beverages
Production on an industrial scale, requires growing microbes in very large
vessels called fermentors.
Microbes especially yeasts have been used from
time immemorial for the production of beverages
like wine, beer, whisky, brandy or rum. For this
purpose the same yeast Saccharomyces
cerevisiae used for bread-making and
commonly called brewer’s yeast, is used for
fermenting malted cereals and fruit juices, to
produce ethanol.
Depending on the type of the
raw material used for fermentation and the type
of processing (with or without distillation)
different types of alcoholic drinks are obtained.
Wine and beer are produced without distillation
whereas whisky, brandy and rum are produced
by distillation of the fermented broth.
antibiotics
*Antibiotics- Chemical substances which are produced by some microbes and
can kill or retard the growth of other (disease-causing) microbes.
*Antibiotics produced by microbes.
*This was one of the most significant discoveries of the 20th century.
*Anti is a Greek word that means ‘against’, and bio means ‘life’, together they
mean ‘against life’ (in the context of disease causing organisms).
*With reference to human beings, antibiotics are ‘pro life’ and not against.
discovery of penicillin
While working on Staphylococci bacteria, once observed a fungus growing in
one of his unwashed culture plates around which Staphylococci could not
grow.
*He found that it was due to a chemical produced by the fungus Penicillium
notatum & he named it Penicillin.
*Full potential of Penicillin as an effective antibiotic was established much later
by Ernest Chain and Howard Florey. This antibiotic was extensively used to
treat American soldiers wounded in World War II.
*Fleming, Chain & Florey were awarded the Nobel Prize in 1945, for this
discovery.
diseases cured by antibiotics
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.
chemicals produced by some microbes
Microbes are also used for commercial and industrial production of
certain chemicals like organic acids, alcohols and enzymes. Examples of
acid producers are Aspergillus niger (a fungus) of citric acid, Acetobacter
aceti (a bacterium) of acetic acid; Clostridium butylicum (a bacterium) of
butyric acid and Lactobacillus (a bacterium) of lactic acid.
Yeast (Saccharomyces cerevisiae) is used for commercial production
of ethanol.
Microbes are also used for production of enzymes
Lipases are
used in detergent formulations and are helpful in removing oily stains
from the laundry. You must have noticed that bottled fruit juices bought
from the market are clearer as compared to those made at home. This is
because the bottled juices are clarified by the use of pectinases and
proteases.
Bioactive Molecules
1.Cyclosporin A-
*Obtained by- Trichoderma polysporum (Fungus)
*Use- As an immunosuppressive agent in organ-transplant patients.
2.Statins-
*Obtained by- Monascus purpureus (Yeast)
*Use- As blood-cholesterol lowering agents.
*It acts by competitively inhibiting the enzyme responsible for synthesis of
cholesterol.
3.Streptokinase or Tissue Plasminogen Activator (TPA)-
*Obtained by- Streptococcus (bacteria)
*Use- As a “clot buster”.
*Remove clots from the blood vessels of patients who have undergone
myocardial infarction leading to heart attack.
