ST NINIAN’S HIGH SCHOOL
INTERMEDIATE 1/ ACCESS 3
BIOLOGY
BIOTECHNOLOGICAL INDUSTRIES
STUDENT SUMMARY NOTES
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1. Dairy Industries
Milk
Milk is an important food for most British people.
Milk contains fat, protein, sugar, vitamins and minerals.
Milk can be
pasteurised
skimmed
UHT
powdered.
The milk all comes from the same source, dairy cows.
It is treated differently to make all these different types.
Milk is an important part of a balanced diet.
It contains many important nutrients, sugar, fats, proteins,
Vitamins and minerals but this makes a good place for
bacteria to grow.
To kill bacteria all our milk is heat-treated in some way.
The heat treatment
bacteria.(Microbes)
should
kill
all
the
The taste of milk is changed by the way it is treated.
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harmful
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Resazurin dye test
To make sure that it is fit to drink before it reaches our
doorsteps or supermarket shelves.
2 main forms of heat treatment: used to destroy harmful
microbes
Pasteurisation
 Pasteurisation is the most widely used heat-treatment.
 86% of the milk sold in this country is pasteurised.

The milk is first heated to 72C for at least 15 seconds.
 It is then quickly cooled to a temperature below 10C.
 It is then packaged in bottles, cartons or containers and
distributed.

Pasteurised milk will keep for up to five days if it is
stored in a fridge.
Ultra High Temperature (UHT)
 UHT milk is heated to a higher temperature than
pasteurised milk.

UHT milk is heated to between 135C and 142C for 2 to
5 seconds.
 This processing alters the taste of the milk.
 Preserves milk and helps it last longer.
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Milk can also be graded by its fat content so that we can buy
Semi-skimmed
skimmed milk evaporated milk
Whole milk is the most popular in the UK.
Semi-skimmed
Skimmed milk
half of the fat removed.
almost all the fat
removed.
Evaporated milk
- half the water taken out
- used like cream
- way to preserve milk
When the fat is removed from the milk there is also a
reduction in Vitamins such as Vitamin A.
For this reason it is not advisable to give skimmed or semiskimmed milk to young children.
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Yoghurt
Making yoghurt is a way of preserving milk.
The yoghurt which we buy in the shops may be set or stirred.
Stirred yoghurt – inoculated
made in bulk
put into pots.
Set yoghurt
- inoculated
incubated in the pot in which it is sold.
You can also find different types of natural yoghurt some of
which are known as bio- yoghurt.
Bio –yoghurt
1.
These natural yoghurts can be used as the “starter”
culture to allow us to make yoghurt in the lab.
2.
The starter cultures contain bacteria.
3.
When the bacteria grow they make lactic acid from the
pasteurised milk.
4.
The lactic acid gives the yoghurt its taste and makes the
milk thicker.
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Cheese
There are several steps in the manufacture of cheese:

the milk is pasteurised to kill most of the bacteria

Rennet is added to milk to make cheese.

The rennet clots the protein in milk to make curds.

Whey is the liquid left when the curds are made.

Bacterial cultures are also added to milk

They convert sugar to an acid which helps clot the
protein.

This can also affect the flavour of the milk.
Rennet
Rennet contains milk clotting enzymes.
The enzyme is used in cheese making and can come from a
variety of different sources:
 rennet from calves
 genetically modified fungi grown in fermenters.
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Monitoring waste
When cheese is made the solid curds go on to form the cheese
but the liquid whey is a waste product.
If the whey was put untreated into the rivers it would cause a
build up of bacteria in the rivers.
These bacteria would use up the oxygen in the rivers and there
would be less oxygen available for the fish and all the other
living organisms. This leads to less living organisms found in the
rivers.
To protect the environment the whey must either be treated
before it is released into the rivers or it must be used for
something else (upgraded).
The whey is treated by using bacteria which feed on the whey
and turn it into carbon-dioxide and water. The bacteria are
then removed and the clearer water is discharged into the
river. The river water is tested to make sure that the oxygen
level is satisfactory.
The whey can be used in industry. Some types of yeast feed
on whey and if they are given the right conditions they change
the sugars in the whey into alcohol. This type of alcohol is
creamy and is found in products such as Baileys Irish Cream.
Whey can also be used to feed animals.
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2. Yeast Industries
Bread
For thousands of years humans have been using yeast in making
bread dough.
Yeast is a simple fungus.
Yeast is added to flour to make the dough rise.
Yeast is a living organism and when it respires( breaths) it
gives out carbon-dioxide. It is this gas from the yeast which
makes the bread rise.
Pure cultures of yeast cells can be grown in huge numbers in
large vessels called fermenters.
The yeast can then be used by the baking industry to make
bread or by the brewing industry to make beer.
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Beer
An alcoholic
drink made
from water,
barley, sugar,
hops and yeast.
In Britain today
there are over
1200 different
brands of beer.
Each brand is
different and
has its own
flavour.
Around half the
beer which is
drunk today is
lager and the other
half is bitter, ale
and stout.
Different beers are brewed in different ways and
they have different alcohol contents.
Making Beer
Factors affecting alcohol content



type of yeast
the temperature
fermentation time
All beer must be matured before it can be drunk.
Maturing the beer improves -
flavour
removes solid material
gives it sparkle
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In beer making yeast converts sugar into alcohol and carbon
dioxide. This process is called fermentation.
The beer is
Cask conditioned beer
Brewery
conditioned beer
- Often called Real
Ale
- for sale in kegs,
bottles or cans
- Made in casks
- stored in large
tanks
- The yeast is not
removed
- yeast is removed
- Fermentation and
carbon dioxide
production
continues in cask.
- carbon dioxide is
added.
-
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this type of beer
such as lager is
therefore clear
and bright and
has a longer shelf
life than cask
beer
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Fermented milk drinks
In many countries it is difficult to keep milk fresh.
One way of solving this problem is to ferment the milk slightly
to make it alcoholic.
An enzyme is added to milk to convert some sugar to lactic
acid.
Yeast is also added and converts some sugar to alcohol and
carbon dioxide.
The product is a fermented milk drink.
In some areas of the world a drink called kefir is made in this
way. Drinking kefir is like drinking a fizzy, slightly alcoholic,
yoghurt drink.
Immobilisation
Used to trap an enzyme and some yeast into a jelly bead.
1. Can be used to make kefir.
2. After the reaction the beads can be washed and reused.
This saves money because the enzymes can be very
expensive.
3. The bead can be easily separated from the product.
4. This would not be possible if the enzyme and the yeast
were free in the yoghurt drink rather than trapped in a
bead.
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Food flavourings and colourings
In addition to using yeast for making bread and alcoholic
drinks, yeast can be used for flavouring food.
Yeast flavourings are added to soups, crisps and snacks.
Wild salmon and trout have pink flesh from the pink coloured
prawns and shrimps which they eat.
Farmed salmon and trout would be a dull grey colour if they
were not fed a red dye in their diet just before they are killed.
The dye does not affect the way that the fish tastes and it is
only added because people do not want to eat grey salmon or
trout.
It is now possible to give the salmon a red colour by feeding
them red yeast. The fish then take on a pink colour in their
flesh.
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Monitoring waste
It is very important that the waste from yeast industries is
not dumped in rivers.
The yeast would provide food for bacteria and the rivers would
become polluted.
Yeast industries treat all their waste and much of it is
upgraded and used for animal feed. This means that the water
leaving the factory can be put into the river without causing
pollution.
Before the water is put into the river it is tested to make sure
that it will not cause pollution.
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3.
Detergent Industries
Biological washing powders
The word detergent means
“something which cleans”.
Soaps, washing up liquid
and washing powder
Some washing powders are known as
biological washing powders.
Biological washing powders contain
enzymes.
Enzymes are produced in large quantities by bacteria cultured
in industrial fermenters and are added to the washing powder
because they improve the way in which it cleans.
Biological washing powder
1% enzymes
water softeners
bleach
chemicals
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The use of enzymes in washing powders
1.
Enzymes in washing powders digest the stains in the
same way that enzymes in your gut help to digest
your food.
2.
Different enzymes are added to digest different
stains.
Fat digesting enzymes are added to digest fatty stains
starch digesting enzymes are added to digest starchy
stains.
3.
The enzymes themselves make up a very small part of the
powder but they make up a large part of the cleaning
power of the powder.
4.
When powders containing enzymes first came into the
shops some people found that they had an allergic
reaction to the powder.
5.
Once this was discovered the detergent industry
introduced new powders where the enzymes had been
coated to prevent allergic reactions, which can cause skin
rashes and eczema.
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6.
Enzymes in washing powders are now all coated with a
waxy substance and they form granules.
7.
The addition of enzymes to washing powders means
that we can all have cleaner clothes as the stains are
digested.
8.
Another major benefit is that these biological powders
work best at low temperatures and this saves energy.
Fuel consumption is reduced which can help in reducing
pollution caused by the burning of fossil fuels in power
stations.
9.
In the past before enzymes were added to washing
powders the temperature of the water had to be much
higher before the clothes would become clean.
10.
The enzymes in the biological washing powders work
best at temperatures of between 40C and about
55C.
11.
The enzymes are destroyed at temperatures above
60C.
12.
The lower temperatures used in washing with biological
powders are also kinder on clothes as high temperatures
can damage delicate fabrics.
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Monitoring waste
Energy is used in
production, packaging and transporting of detergents
greatest use of energy is in the home.


In the home
Heating the water for the washing machine, the wash
cycle, tumble drying and ironing all use up energy.

This means that it costs the consumer a lot of money and has a
great impact on the environment.
Saving energy
1.
2.
3.
4.
Washing clothes at low temperatures.
Reduces fuel consumption.
Contributes to reducing pollution caused by the
burning of fossil fuels in power stations.
Less fuel will be used and this is good news for the
consumer and for the environment.
Detergents in waste water can be toxic to wildlife
Detergents all end up in the environment when they are flushed
away as waste water.
Detergents contain other chemicals which can increase the
growth of algae in lakes and rivers.
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When algae die this can have the same effect as whey released
into rivers.
The manufacturers test their products to see that they would
not harm the fish or the other living organisms found in our
rivers.
The detergent industries check their own waste.
Ways to reduce environmental impact


reduce the chemicals in detergents
sewage works removing the chemicals before releasing
the water into the environment.
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4. Pharmaceutical Industries
Produced
naturally by
fungi from soil
Penicillin most common
antibiotic
Destroy and prevent
the further growth of
bacteria.
Antibiotics
There are
many
different
types of
antibiotic.
They were
discovered
by Alexander
Fleming.
Produced commercially
in automated industrial
fermenters.
Only act on
bacteria and not
on viruses.
1.
Around the time of the Second World War two other
British scientists managed to produce penicillin on an
industrial scale.
2.
Antibiotics then became known as the “wonder drug” they cured so many people who would have died.
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Making Antibiotics
1.
To meet the massive demand for antibiotics in the
modern world huge fermenters holding over 200,000
litres have been designed.
2.
Careful attention has been paid to produce the best
growth conditions and the vessels are automated and
controlled by computers.
6.
Sterile conditions must be maintained in the fermenter.
7.
Growth conditions are altered automatically by the
computers for example if the temperature in the
fermenter becomes too warm the computer detects the
change and cools down the mixture.
8.
Finally the antibiotic has to be purified - this involves
filtering and solvent extraction.
Genetic modification;
- is a new technology which alters the genes
found in living things.
- can be used to produce new antibiotics which will be more
effective for fighting disease.
- Computer-control technology is used to monitor and
adjust growing conditions, e.g. temperature
- Computer- control can help purification of the antibiotic.
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Advantages of antibiotics
1.
Different antibiotics are effective against different
infections.
2.
Penicillin is used to treat a wide range of infections
including respiratory infections.
Disadvantages of antibiotics
1.
When antibiotics first appeared they were considered to
be the wonder drugs but after some time it was found
that some infections became resistant to the antibiotic.
2.
This means that the drug no longer kills the bacteria
which is causing the infection.
3.
This has happened because of over-use of penicillin and it
is a very worrying trend.
4.
People are now also concerned about the over-use of
antibiotics in Agriculture and veterinary practice.
5.
The same drugs are used in animals as in humans and the
concern is that over-use of antibiotics in animals might
lead to more resistant strains of bacteria.
There is continual pressure to try to produce new antibiotics
which bacteria are not resistant to.
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Anti-fungals
Some infections are caused by microbes known as fungi.
Some common fungal infections are
thrush
athletes foot
Drugs known as anti-fungals can be used to treat these
infections.
The anti-fungal treatment slows down or stops the growth of
the infection.
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