Topic 5 - Biotechnology


23 Οκτ 2013 (πριν από 4 χρόνια και 8 μήνες)

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Topic 5


Topic a

Living Factories

You should know that:

the raising of dough and the making of beer and wine depend on the activities


yeast is a single celled, microscopic fungus which uses sugar as food.

fermentation is another name for the release of energy from food without
using oxygen

yeast ferments glucose the process can be represented by the following
word equation:



the term
"respiration" describes any chemical process which releases energy
from food

there are two types, depending upon whether oxygen is available or not.


which uses oxygen


which happens when no oxygen is

aerobic respiration produces much more energy from a given amount of food

anaerobic respiration (fermentation) produces much less energy

anaerobic respiration produces alcohol (ethanol) as a waste product/by
product when it happens in plants or
fungi such as yeast
respiration produces lactic acid as a by
product when it happens in animals
and bacteria

commercial brewers make sure that beer production is as efficient as
possible by providing the best possible conditions for yeast to gr
ow and

this means that the temperature, oxygen supply and amount of glucose must
be carefully controlled, and unwanted

organisms must be kept out.

the easiest way to make sure that this happens throughout the fermentation
is to set up all the

conditions at the start, together with the raw materials,
and then to leave the whole system closed and untouched until the
fermentation is complete

this has the disadvantage that production is only possible in batches rather
than a continuous process


production process like this is called "batch processing"

the brewing industry uses barley as the source of the food which the yeast
ferments to make the alcohol in beer

however barley stores food in the form of starch

which is a type of food
yeast cannot use

in order to solve this, the brewer allows the barley grains (seeds) to

enzymes in the barley then convert the starch into maltose sugar, which the
yeast can ferment

this process is called malting

making cheese and yoghurt are al
so processes which depend upon micro

in this case, bacteria.

the souring of milk
is a fermentation process

contains sugars and some bacteria

the bacteria feed on the sugars in the milk

the main sugar in milk is called lactose


is converted into lactic acid by bacterial fermentation,

the increased acidity makes the milk turn sour

Topic b

Problems and Profit with Waste.

You should know

the disposal of untreated sewage causes several types of damage to the
environment; for example;

it lowers the oxygen concentrations of rivers due to bacterial

and lowers their pH (i.e. makes them more acidic)

untreated sewage can also spread diseases caused by poisons
and harmful micro
such diseases inclu

food poisoning, polio, dysentery and cholera.

it is very important to take careful precautions when working in the
laboratory with micro

some of the main precautions are:

use of lab coats, overalls, gloves and masks as necessary

areful washing of hands

sterilising lab benches and use of sterilised equipment

no food or drinks in the lab

careful disposal of microbes using high temperatures

these precautions are needed in all biotechnological processes

prevent the escape

of harmful organisms
to the surroundings

avoid contamination

of pure cultures of microbes by

unwanted other types entering
from the surroundings

precautions during manufacturing processes are just as important

a particular danger in these case
s are spores of bacteria and fungi
resistant to normal hygiene measures.

careful and regular checks must be made for contamination

very high temperatures and
or suitable chemical methods are often used for

both important
and useful, since it recycles raw materials and gets
rid of waste at the same time.

decay is the decomposition of organic matter by micro

the micro
organisms feed on the organic matter to provide themselves with

some bacteria [and some fun
gi) are involved in the process of decay

during the decay process both carbon and nitrogen are recycled

the carbon from dead or waste materials is made into carbon dioxide which
plants need for photosynthesis

the nitrogen from proteins in dead or waste mat
made into nitrates in
the soil which plants use as nutrient to
produce new proteins.

in sewage treatment works the main process is the breakdown of the waste
by the action of decay micro
organisms to products harmless to the

organisms need lots of oxygen to do their job properly, and this is
provided both by stirring the waste mechanically, or by injecting jets of
compressed air

the reason for the need to provide lots of oxygen to the bacteria in sewage
treatment works

anaerobic respiration by bacteria only partly breaks down the waste.

plentiful oxygen means that the bacteria use aerobic respiration

aerobic respiration makes the breaking down process complete

sewage contains a wide variety of waste materials

different types of micro
organism feed on different waste materials

this means that a range of different micro
organisms must be provided so
that all the waste can be broken down.

examples of useful products which can be gained from waste materials

the action of micro
organisms are:

biogas (mainly methane) which is produced from organic waste such as
sewage sludge and domestic refuse

high quality protein foods from waste such as whey (from cheese
making) or fruit pulps (after juice extraction)

this technology is important economically because useless, and possibly even
poisonous substances are converted into useful substances such as food and

the main aim in upgrading waste
to convert it to more useful substances.

most commonly this invo
lves raising the levels of protein, or increasing the
energy content of the waste.

alcohol and methane are both valuable fuels

each of them can he produced by fermentation of suitable plant crops

the production of fuel in this way has certain advantages o
ver the production
and use of fuels from fossil sources such as coal and oil

some of the advantages are:

it uses raw materials which are renewable as opposed to fossil
fuels which must run out eventually

in many cases it allows countries with no coal or
oil to produce
their own fuel

the raw materials used may often be the waste from other
production processes which could otherwise be harmful and/or
difficult to dispose of

burning them produces less atmospheric pollution than fossil


suitable conditions micro
organisms can reproduce very rapidly by
asexual methods.

these micro
organisms can be harvested to provide protein rich food for
animals or man


Reprogramming Microbes

You should know that:

the control of all the

normal activities of a bacterium depends upon its

in genetic engineering pieces of chromosome can be transferred from a
different organism

this allows the bacteria to make new substances

this process involves several steps

identifying useful g
enes in other organisms

separating the required gene from the rest of its chromosome

inserting the gene into a "host" cell (usually bacterial)

reproducing the cell which now contains the new chromosomal material

as a result of genetic engineering it is pos
sible to use bacteria to produce
increased quantities of many products
genetic engineering also speeds up
the process of producing many substances

genetic engineering
a way of producing organisms
have genotypes
best suited for a particular funct
in the past man has used selective
breeding to achieve this

this was done by choosing only his most suitable animals and plants for
breeding from

genetic engineering has several advantages over selective breeding as a


single characteristics can be selected

the selection may be quicker

a desirable characteristic can be transferred from one species to

genetic engineering is used for the production of substances which used to be
both expensive and difficult to pr
oduce, examples include:

insulin for the control of diabetes

antibiotics such as penicillin

various vaccines for the control of disease

a particularly successful example of the benefits of biotechnology

the need for it
rapidly increasing fo
r many reasons;

diabetes often doesn't occur until old age and more people are now
living to old age

it is now also becoming more common in young people

people live longer, and better treatment means many more patients
survive to old age

purifying insuli
n from the pancreas of slaughtered cattle and pigs was
slow and expensive

animal insulin was not as effective as human insulin

some patients were allergic to animal insulin

some patients did not like using a product form slaughtered animals


insulin produced by bacteria as a result of genetic engineering is
pure human insulin

its production is both quick and relatively cheap

it has none of the problems associated with the use of cattle or pig

there are dangers involved with genet
ic engineering since it involves creating
completely new strains of bacteria.

the possibility therefore exists of creating some which might be harmful to
animal or plant life.

biological detergents contain enzymes produced by bacteria.


of the stains on clothes are proteins [blood, grass, gravy etc. etc.]

the enzymes [such as proteases} break down and digest proteins

this allows easier removal of the stains.

the enzymes work at relatively low temperatures

they remove stains which would
otherwise need high temperature

this saves energy and money by allowing low temperature washes.

it also helps to get delicate fabrics, which would be damaged by a very
hot wash, properly clean.

an antibiotic is a chemical which prevents the growth
of micro

there are many diseases, each caused by different bacteria

different bacteria are affected by different antibiotics

one antibiotic may only work against certain types of bacteria

this means that a range of different antibiotics is neede
d for the treatment
of bacterial diseases.

immobilisation techniques restrict the movement of enzymes or cells.

this is usually done by attaching them to beads of jelly or other carrier

immobilisation techniques allow continuous flow processing

by effectively
keeping the enzymes or cells separate from the product.

the product formed is exactly the same as it would be without immobilisation

the time & costs of purifying the product by separating it from the enzymes
is greatly reduced since the en
zymes/cells are unable to spread through the

the enzyme
cell remains inside the fermenter, whilst the end product flows

this results in increased productivity and reduced costs compared to batch


flow processing usually works out faster, cheaper and more
efficient than batch processing.