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BIOTECHNOLGY
It is the application of biological organisms, systems or processes to manufacturing & service industries. Microbes,
plant & animal cells are used to make substances that are useful to human beings.
Why Micro-organisms are used in Biotechnology
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Savings on fuel because they carry out reactions at moderate temperatures.
They are very efficient because they produce purer products & less waste.
They can be genetically engineered to produce compounds needed for humans.
The Role Micro-organisms in Food Production
Making Bread.
The enzymes in yeast act on the sugar added to the flour & ferment it to alcohol & carbon dioxide which makes
the dough to rise.
Sour Milk (madila)
The milk is put into a large container & bacteria (lacto bacillus) are added to ferment the milk. The bacteria
converts the milk sugar (lactose) to lactic acid. The lactic acid will coagulate (solidify) the milk protein. Water will
then remain at the bottom of the container & coagulated protein floats on top. The mixture is sieved to remove the
waste water from the curd or sour milk. At this stage the milk is sometimes stirred to obtain evenly thick & smooth
sour milk. Then the sour milk will be ready for packaging & distribution.
Chibuku ( traditional brew)
Mealie meal, water & malt are mixed & left to ferment & this mixture is called wort. This is the first fermentation
process, the enzymes found in the malt brake down starch (mealie meal) to maltose & glucose & then ferment
these sugars to alcohol. After this fermentation, the mixture is cooked at 970C for about one hour. Yeast & lactic
acid are added. Lactic acid gives chibuku its sour taste. The second fermentation process will then occur. The
yeast cells will then ferment maltose & glucose. (sugars from the first fermentation) to produce alcohol. After the
second fermentation process, the mixture is then served. Chibuku is pasteurized, before packaging to kill both
yeast cells & any other micro-organisms
Single Cell Protein
The aim here is to produce food in bulk using micro-organisms or the organism being the food itself. It can be
used to feed humans & animals. Filamentous fungus which is very rich in proteins can be produced in large
amounts & be used as a meat substitute. It contains a lot of dietary fibre & very little amount of fat. Unicellular
algae, fungi & bacteria have been used.
Wine
It is made from grapes & these are crushed to release sugar. The yeast found on the grape skin ferments the
sugar to make wine.
Yoghurt & cheese
Bacteria are used to ferment milk to form yoghurt & cheese. The bacteria act on the milk sugar (lactose) &
convert it to lactic acid, which in turn coagulates the milk protein, casein to produce a thick creamy substance
(yoghurt). The lactic acid gives the yoghurt its slightly sour taste. In cheese making, the mould can also be
involved e.g. adding spores of penicillium at the fermentation stage to give varieties of cheese.
The Role of Micro-organisms in Fuels & Other Chemicals
 Fuel
In some countries e.g. Brazil, yeast is used to ferment sugar from sugar cane to alcohol (ethanol). The
ethanol is distilled & then concentrated to about 96% alcohol. Pure alcohol will burn in the same way as
petrol. It is used in car engines that are specially adapted. Unlike petrol, it does not pollute the atmosphere.
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Micro-organism can be used for production of bio-gas, e.g. methane gas. This gas can be produced from
decomposing cow dung using bacteria. This gas can be used as a substitute fro the gas used fro cooking,
which is fossil fuel.
 Biological Enzyme Washing Powders
When washing powders are prepared, some biological enzymes are added to help in removing stains from
clothes, e.g.
- The enzyme lipase will act on fat stains & make easy to wash the clothes.
The proteases would act on protein stains & remove the much faster & easier, e.t.c
The Role of Micro-organisms in Genetic Engineering
Genetic engineering is the transfer of genes from one organism to another of a different species. Genetic engineering
has been found to solve most problems, e.g.
Making insulin for people who are unable to produce it.
Replacing faulty alleles with normal alleles (Gene therapy)
Producing plants that are often resistant to diseases e.t.c
Bacteria are simple organisms & are often used in genetic engineering because they are easy to manipulate, since
their DNA called plasmids are not enclosed in a nuclear membrane.
 Insulin Production
A gene for insulin production in humans can be removed from the human cell & be pasted / attached to the DNA of
Escherichia coli (E.coli), a bacterium that lives in the human digestive tract. Special kinds of enzymes of called
restriction enzymes are used to cut in a very precise way, a specific base sequence of the DNS molecule to remove
targeted gene, which in this case will be the gene for insulin production. This cut of the DNA will then be attached to a
cut portion of the plasmid (bacterial circular DNA) using an enzyme called DNA ligase. The plasmids with the attached
human DNA will than be taken back into the bacterial cell where they start controlling the activity of the bacterial cell.
One of the instructions will be to produce insulin, which can then be extracted and used to help those people who need
it. The bacterial cells divide very rapidly making billions of copies of themselves and each bacterium will be carrying in
its DNA a true copy of the gene for insulin production, i.e. each bacterium cell inherits the human insulin gene.
 Gene Therapy
It involves the use of genetic engineering to replace defective / faulty genes with normal genes. This is sometimes
done to correct hereditary diseases such as haemophilia, sickle cell anaemia, cystic fibrosis e.t.c. cystic fibrosis is
a disease in which the person lacks a gene which encodes for cell membrane protein. This results in cells, especially in
the air passages, producing a lot of thick & sticky mucus. In this case, the normal gene can be introduced into the
patient’ lungs by using a harmless form of flu virus. It is hoped, once inside the body that the DNA with the normal gene
can be incorporate itself to the DNA of the body cell & thus correcting the disease. If a normal gene is inserted in any
body cell not a sex cell to correct a particular disorder, it cannot be passed on to future generations & this is called
Somatic gene therapy. It the healthy gene is inserted into a the fertilized egg of a human being or an animal that has
a specific genetic defect, then it will be passed to the future generations resulting in the normal offsprings. This is
called Germline cell therapy.
 Crop / plant Resistance
Genetic engineering can be used to induce resistance in plants / crops in terms of resistance to diseases, pests or
environmental conditions such as drought, frost, wind etc. a gene may be inserted into the plant to enable it to produce
an insecticidal crystal protein which may affect the gut of pests e.g. caterpillars so that they cannot feed & eventually
die. Some genes transferred into the plant may make it resistant to herbicides. The field of growing crops can then be
sprayed with the herbicides which will selectively kill the weeds since they do not posses the resistance gene. Genetic
engineering can be used to produce plants with thicker & waxier cuticle which grow well in more arid areas. Some may
be engineered to have stronger stems of a more uniform height to be resistant to wind damage.
The Role of Micro-organism in the Production of Medicine (Antibiotics & Vaccines)
Vaccines
They are prepared from dead or inactivated (harmless) micro-organisms {germs} and given to people to immunize
them against diseases, e.g. measles, polio, small pox etc. these germs still have antigens which will provoke the
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human body to produce antibodies just like active germs do. These antibodies will be ready to fight germs the moment
they invade the body.
Antibodies
These are chemicals that are used to kill germs. E.g. penicillin which is produced by a mould. Penicillium is used to
cure bacterial diseases e.g. syphilis & gonorrhea.
This was discovered by a scientist named Alexander, who was growing bacteria on agar plates, but he left one of the
plates open by accident & a mould started to grow on the surface. He noticed that the mould was stopping the bacteria
from spreading; it seemed to be making a substance that killed the bacteria. Eventually the substance was extracted &
used to cure bacterial diseases. The antibiotic, streptomycin is produced by bacteria called streptomyces.
Courtesy of Lebsy Mb
Contact; 71726846