Transcript Biotechnology

Biotechnology
Unit 1 : Dairy Industries
i. Milk
ii. Yoghurt
iii. Cheese
iv. Environmental
Impact
i. Milk
• Milk is an important food for most
British people.
• It is an important part of a balanced
diet
• Milk contains:
fat
starch
sugar
protein
minerals
Milk treatment
All milk comes from dairy cows.
It is treated in different ways to
produce different types.
Milk is available in forms such as:
pasteurised
skimmed
UHT (ultra high temperature)
powder
Heat treatment of milk
• Milk is an ideal place for
bacteria to grow.
• Some bacteria are harmful so all
milk is heat treated to kill them.
• Common methods of heat
treating are by:
pasteurisation
Ultra High Temperature
Pasteurisation
Most milk is treated by pasteurisation.
Method:
1. Heat milk to 72ºC for 15 seconds.
2. Cool quickly to below 10ºC.
3. Pack in bottle, carton or container.
Pasteurised milk will keep for up to
five days in a fridge.
Ultra High Temperature
•UHT milk is heated to a higher
temperature than pasteurised
milk.
UHT milk is heated to 135oC142oC for 2-5 seconds.
•This process alters the taste of
milk.
Resazurin Test
• Resazurin dye is a chemical that
changes colour in response to
the number of bacteria in a
liquid.
• Can be used to tell us if milk is
fit to drink.
Colour of
sample
Blue-purple
Bacterial
content
Very low
Drinking
quality of milk
Good
mauve
low
Satisfactory
pink
medium
Poor
white
high
unsatisfactory
Experiment: resazurin
test
Fresh milk
+ resazurin
5 day old
milk +
resazurin
10 day old
milk +
resazurin
Results:
Time
(min)
0
5
10
15
Fresh
milk
5 dayold
milk
10 dayold
milk
Fat content of milk
Milk can be graded by its fat content:
Type of milk
Whole milk
Fat removed
none
Semi-skimmed
half
skimmed
almost all
Evaporated milk has ½ the water removed
and is used like cream.
Content of milk (continued)
• Removing fat from milk reduces
vitamin content e.g. Vitamin A
• Skimmed and semi-skimmed milk
have fat removed so the vitamin
content is reduced.
• Young children should be given
whole milk which has more vitamins.
ii. Yoghurt
• Milk can be preserved (made to
last longer) by changing it into
yoghurt or cheese.
• Natural yoghurt can be used as
‘starter cultures’ to make
yoghurt in the lab.
Making Yoghurt
• Starter cultures contain special
bacteria that make lactic acid from
the sugar (lactose) in the milk.
lactose
(sugar in milk)
lactic acid
(thickens and gives taste)
• Lactic acid thickens the milk and
gives the yoghurt its taste.
Making yoghurt
Method
1.
Heat milk to 43oC (helps bacteria grow)
2.
Add 1 teaspoon of starter culture (natural
3.
Cover with cling film.
4.
Incubate yoghurt at 43oC for 7 hours.
5.
When ready, place yoghurt in fridge for 4
hours.
yoghurt)
Types of Yoghurt
There are different methods for
making yoghurts:
1. Stirred yoghurts – bacteria is
added to the batch. It is then put
in to pots when ready.
2. Set yoghurts – bacteria is added
then the mixture is put straight
into the pots where it sets.
Aseptic conditions
• Air contains many types of
microbe.
• Many are also present in dust as
tiny clumps called spores.
• During experiments, certain
precautions should be taken to
create sterile (aseptic)
conditions.
• This is done for two reasons:
– To stop unwanted microbes getting
into the experiment and spoiling it
– To stop ant microbes used in the
experiment escaping.
• 1. Hands should be washed, cuts
should be covered.
• 2. Work surfaces should be
disenfected.
• 3. Lab coats should be worn
• 4. All equipment should be
sterilised in an autoclave
(heated to 121C for 20 mins).
iii. Cheese
Making Cheese
•
Milk is pasteurised to kill most bacteria.
•
Special bacteria are added to convert
milk sugar (lactose) into lactic acid.
•
Enzymes (rennet) are added to clot the
proteins in milk to form solid cheese.
Types of rennet
Milk clotting enzymes (rennet) can come from different sources.
Type of
rennet
Source
Advantage
Disadvantage
Calf
rennet
calves
Original source,
used for centuries.
Animals must
be killed, risk of
disease
Fungal
rennet
fungus
Cheap, large
amounts, OK for
vegetarians.
taste
GM yeast yeast
rennet
No animals
Public concern
involved, OK for
about
vegetarian, same as genetically
animal rennet.
modified foods
iv.Environmental Impact:
Monitoring Waste
• Cheese making uses the enzyme
rennet which makes the milk
proteins clot to form curd.
• The liquid left is called whey.
milk + rennet
curds (solid)
cheese
whey (liquid)
waste product
Whey and pollution
• Whey contains sugar. What would happen if
whey was released into rivers?
1. Bacteria would use the whey sugars as
food and reproduce.
2. As the number of bacteria increased it
would use up the oxygen so oxygen levels
would decrease in the water.
3. Fish and other living organisms would
start to die as the oxygen level decreased.
Pollution prevention
To prevent pollution whey
can be:a. treated before release
b. upgraded (used for
something else)
Treatment of whey
• Add bacteria which feed on whey and
turn it into carbon dioxide and water.
• Remove bacteria and release cleaner
water into river.
• Test water oxygen level to make sure
it is OK.
Upgrading whey
• Waste whey used as food for growing
some types of yeast.
• In the right conditions these yeast
strains produce alcohol from the
sugars in the whey.
• Alcohol produced is creamy (found in
Baileys Irish Cream)
Preventing pollution
Monitoring waste
Waste whey
Treat with bacteria
Upgrade
bacteria feed on whey
carbon dioxide and water produced
bacteria removed/clean water released
whey used as food for yeast
yeast produces creamy alcohol
used in production of Baileys Irish Cream
Biotechnology
Yeast Industries
i.
ii.
iii.
iv.
v.
Bread
Beer
Fermented milk
drinks
Flavouring and
food colouring
Environmental impact
i. Bread
Yeast:
• a single-cell fungus (plant)
• used in bread-making for 1000’s of
years
• is added to flour to make bread rise
(dried or fresh yeast – activity 2.1)
Yeast (continued)
• Yeast is a living organism.
• It respires to release carbon
dioxide.
• It is the carbon dioxide that
makes bread rise.
Growing yeast
• Huge numbers of pure yeast can be
grown in large vessels called
fermenters.
• This yeast can be used in the baking
or brewing industry to make bread
or beer.
• Cultures of pure yeast can be grown
on an agar plate.
ii. Beer
Beer is an alcoholic
drink made from:
water
barley
sugar
hops
yeast
The role of yeast in
making beer
sugar
yeast
alcohol + carbon dioxide
+ energy
Yeast uses sugar to release energy.
During this process, called fermentation,
alcohol and carbon dioxide are released.
The gas carbon dioxide is what makes the
beer fizzy.
Ales and lagers
• Different strains of yeast give
different ales and lagers.
• These yeasts use the sugars at
different rates and at different
temperatures.
Ale and lager yeasts
Type of
yeast
Growth
temp
Time to
grow
Ale
12-18ºC
6 days
Lager
8-12ºC
21 days
Position
of yeast
in
vessel
Rise to
top
Sink to
bottom
Making beer
• There are over 1200 different brands of
beer in Britain each with its own flavour.
• Around half the beer is lager, the rest is
bitter, ale and stout.
• Different beers are brewed in different
ways and have different alcohol contents.
• Traditional beers have around 4% alcohol
(activity 2.3)
Alcohol contents of beer
(Activity 2.4)
Drink
Lager
Barley ale
Low alcohol beer
Alcohol free beer
Wine
Vodka
Whiskey
Alcohol Content
Alcohol contents of beer
(Activity 2.4)
Drink
Alcohol Content
Lager
4%
Barley ale
11%
Low alcohol beer
1%
Alcohol free beer
0.05%
Wine
12%
Vodka
40%
Whiskey
40%
Maturing the beer
Beer must be matured before it
can be drunk.
Maturing beer:
– Improves flavour
– Removes any solids
– Gives ‘sparkle’
(activity 2.6)
Beer can be:
– cask conditioned
(often called real ale)
– brewery conditioned
(kegs, bottle, cans)
Cask conditioned beer
• Cask conditioned beer is put into
casks (huge containers made
from wood or steel)
• Sugar is added to the cask.
• Yeast still producing carbon dioxide
which makes the beer ‘sparkle’.
• Beer produced is dark with a strong
flavour.
Brewery conditioned
beer
• Stored in large tanks
• Sold in kegs,
bottles or cans.
• Remains of yeast and other solids
removed.
• Beer (e.g.) lager is clear and bright.
• Long shelf life (keeps for a long time)
Differences : cask conditioned
and brewery conditioned beers
(Activity 2.6)
Example of
type of beer
produced
Storage
conditions
Description
of beer
Cask
Brewery
conditioned conditioned
beer
beer
Differences : cask conditioned
and brewery conditioned beers
(Activity 2.6)
Example of
type of beer
produced
Storage
conditions
Cask
conditioned
beer
Real ale
Casks
Sugar added
Yeast present
Description of Dark colour
beer
High flavour
Brewery
conditioned
beer
e.g. Lager
Keg beers
Bottles/cans
Large tanks
Yeast
removed
Clear/bright
Lasts longer
iii. Fermented Milk
Drinks
In many countries it is difficult
to keep milk and yoghurt fresh.
The milk can be fermented
slightly to make it alcoholic.
Yeast is used to turn the sugars
in milk into alcohol.
Making fermented milk
drinks
(activity 2.7/2.8)
• Kefir is a refreshing, fizzy,
slightly alcoholic, yoghurt drink.
• This drink can be made by a
method called immobilisation.
Making Kefir
Step 1
Sodium alginate + lactase (enzyme that
Add wine yeast
Add calcium chloride
drop by drop
(hardens beads)
Immobilised beads
breaks down
lactose)
Step 2
Warm milk
Add live yoghurt
Add Immobilised beads
Leave at 43ºC for 5 hours
Filter mixture to give
fermented milk drink
Beads
can be
re-used
kefir
Immobilisation
Immobilisation can be used to trap
an enzyme and some yeast into a
jelly bead.
jelly coat
yeast + enzyme
Advantages:
1.
2.
3.
After the reaction the beads can be
washed and re-used.
Saves money (enzymes are expensive)
Bead easily separated from product (e.g.
by filtering)
iv. Food flavouring
• Yeast can be used for:
– Making bread
– Alcoholic drinks
– Flavouring food
• Foods with yeast flavouring:
– Meat flavoured crisps e.g.
chicken,bacon
– Oxo cubes
– Marmite
(activity 2.9)
Food colourings
(activity 2.10)
• Wild salmon and trout have pink flesh.
This colour comes from
the pink coloured prawns
and shrimps they eat.
• Farmed salmon would have grey flesh but
they are fed red dye just before they are
killed which makes their flesh pink.
Red dye
• Feeding dye doesn’t affect the
flavour but makes their
flesh more appealing to eat.
• Now red yeast can be fed to the fish.
This gives a pink colour to their
flesh.
Red yeast
v. Environmental Impact
• Waste from yeast industries should
not be dumped in rivers.
• Yeast would act as food for bacteria
which would cause pollution.
Getting rid of waste
• Waste can be
upgraded and
used for animal
feed.
• Treated water should
be tested before
releasing into rivers.
The methylene blue test
We are going to test some water samples
to see if they could be put into a river.
Collect: samples A, B and C
3specimen tubes+lids
3 labels
dropper
measuring cylinder
methylene blue dye
Testing water samples for
pollution:
The Methylene Blue Test
Time
Immediate
2-3 days
4-5 days
4-5 days
Colour
change
Water
condition
Pollution
scale
The methylene blue test
Time
Colour
change
Immediate Blue to
clear
Water
condition
Dangerou
s for river
Pollution
scale
Very
polluted
2-3 days
Dangerou
s for river
Needs
more
treatment
Safe for
release
Very
polluted
Slightly
polluted
4-5 days
4-5 days
Blue to
clear
Blue to
clear
Still blue
Not
polluted
Detergent Industries
Enzymes in washing
powders
The word detergent means
‘something that cleans’ e.g.
soaps
washing up liquid
washing powder
Biological washing
powders
Biological washing powders
contain enzymes.
Enzymes are chemicals that
improve the way in which the
powder cleans.
What is biological washing
powder made of?
Biological washing powder is
made up of:
• 1%
enzymes
• 99%
water softeners
bleach
other chemicals
(to help
water get into the clothes)
Where do the enzymes
in washing powder
come from?
• Bacteria are tiny organisms found almost
everywhere on Earth.
• Scientists found bacteria that were harmless and
produced enzymes that could be used in washing
powders.
• Large numbers of these bacteria grow (cultured)
very quickly in huge industrial fermenters that give
the best conditions for growth.
• Enzymes produced are then separated from the
bacteria and used to make biological washing
powder.
The use of enzymes in
washing powders
Enzymes in washing powders digest the
stains on clothes like enzymes in the gut
digest food.
Different enzymes digest different stains.
– Fat digesting enzymes digest fatty
stains.
– Starch digesting enzymes digest fatty
stains.
Enzymes make up a
but a
small
part of powder
large part of the cleaning power!
Activity 3.1: To show how an
enzyme can remove a stain
• Stains from food like eggs contain
protein.
• Photographic film has protein on its
surface.
Protein
‘stain’
In the following experiment, enzymes
like those in biological washing
powder are used to remove the ‘stain’
on a piece of photographic film
Expt. : To investigate the effect of
enzymes on a protein stain
Method:
•
•
•
•
•
•
•
•
Collect 2 test tubes.
Label test tubes A and B
Add 1 piece of film to each test tube.
Half fill tube A with enzyme
Half fill tube B with water
Shake each tube
Put tubes in water bath at 50oC for 30
mins – shake tubes every 5 mins
Remove film, dry and examine.
Tube
contents
Film + Enzyme
Film + water
Protein
digested?
Comparing biological and nonbiological washing powders
• Biological washing powders contain
enzymes.
• Non-biological washing powders do
not contain enzymes.
• This experiment compares the ability
of these two types of washing
powder to remove different stains
Comparing bio and nonbio washing powders
Warm
water + bio
powder
Stained
cloth
Warm
water +nonbio powder
Stained
cloth
Stain
Removed with Removed with
bio powder?
non-bio
powder?
Disadvantage of biological
washing powders
• Original biological washing powders
sometimes caused an allergic
reaction in some people.
• This caused skin rashes, eczema and
asthma.
• New powders are now produced with
enzymes enclosed in a harmless
waxy coating.
• This helps to prevent allergic
reactions.
(Activity 3.3)
Advantages of
biological washing
powders (Activity 3.4)
1. Adding enzymes to biological washing
powders means cleaner clothes (stains
are digested).
2. Work best at low temperatures 40oC - 55oC
(temperatures above 60oC destroy
enzymes) so need to heat clothes to high
temperatures to get them clean-saves
energy and money.
3. Lower temperature used with biological
washing powders reduce damage to
delicate fabrics.
Environmental Impact :
Monitoring Waste
Making detergent uses energy for:
• Production
• Packaging
• Transporting
But most energy is used in the home
for:
• The wash cycle
• Tumble drying
• Ironing
Detergents and energy
Activity 3.5
To provide all the energy
needed power stations burn
coal, oil or gas.
This gives off carbon dioxide
and sulphur dioxide that
pollute the atmosphere.
Low temperature wash = less energy
good for public and environment!!
One manufacturer of detergents has
set targets for waste management:
•
•
•
•
Reduce weight and volume of packing
Use reusable materials
Encourage recycling programmes
Encourage safe disposal practises
New ‘Micro’ powders and liquids use less
packaging and powder for each wash.
Detergents and the
Environment (Activity 3.6)
• Detergents are flushed away as
waste water and can pollute the
environment.
• Detergents can be toxic
(poisonous) to wildlife.
• Manufacturers test products to
check they won’t harm fish or other
living organisms in rivers.
Detergents containing phosphates
and sulphates pollute river
Tiny plants (algae) reproduce quickly to
form ‘bloom’
Algae die
Bacteria feed on dead algae
Number of bacteria increases
Bacteria use up oxygen in water
Fish and animals die
Reducing Environmental
Impact
• Detergents in water tested at
sewage works in mini sewage plants
• Sewage plants could remove the
phosphates and sulphates to reduce
environmental impact
• Using low phosphate detergents can
also reduce environmental impact
Washing clothes in
other countries (Activity 3.7)
• Most people in the world
wash clothes by hand
• Washing machines in other countries
are different from those in the UK
In the USA washing machines
are bigger and use more water
In Japan and Taiwan washing machines
do not heat the water. Clothes are presoaked and washed more often
Biotechnology
Unit 4 : Pharmaceutical
Industries
i.
ii.
Antibiotics
Antifungals
Antibiotics
~ discovered in London in 1928 by Alexander
Fleming (Scottish scientist)
~ He was growing bacteria on agar plates to
study.
~ One of his plates had been contaminated with
a fungal spore and he noticed no bacteria
would grow near it
~He found out that fungi produce chemicals to
stop growth of competing bacteria
~These chemicals are called
antibiotics
~The antibiotic Fleming had
discovered was penicillin and had
been produced by the fungi
penicillium
~Different types of antibiotics kill
different bacteria – but not viruses
like those causing flu or the cold.
• Other scientists developed ways of
extracting peniciliin fron the fungus
and purifying it
• The first man to be treated with
penicillin was a policeman.
• He was ill from blood poisoning and
not expected to live more than a
few hours.
• When injected with penicillin there
was a huge improvement in his
condition.
• The man only died when the
antibiotic ran out after ten days.
~Different types of antibiotics kill
different bacteria – but not viruses
like those causing flu or the cold.
• Penicillin now cures diseases such
as pneumonia and diptheria
Antibiotic action
• If an antibiotic can inhibit growth of
a species of bacteria we say the
bacteria is sensitive to that
antibiotic
• If an antibiotic has no effect we say
that species of bacteria is resistant
to the antibiotic.
• There is no one antibiotic that works
against all species of bacteria
Antibiotic
Pneumonia
Tuberculosis
Typhoid Diptheria
penicillin
+++
-
-
Streptomycin
-
+++
+++
-
-
Tetracycline
+++
-
+
++
Cloramphenical
+++
-
+++
++
+ + + = very effective
++
= effective
+
= slightly effective
-
= no effect
• Different antibiotics
have different
methods of
destroying bacteria:
– Some destroy bacterial
cell walls
– Some burst the cell
membrane
– Some interfere with
the bacterial cell’s
chemical reactions
Different types of
antibiotics
(Activity 4.3)
Different antibiotics are effective
against different infections.
Antibiotic
penicillin
Infection which it treats
aminoglycosides
respiratory infections
(and many others)
Eye and skin infections
fluoroquiniles
Gonorrhoea (STD)
cephalosporinc
Urinary infections
tetracyclines
acne
Choosing the correct
antibiotic
• When a patient has
an unknown
bacterial infection, a
sample of body fluid
taken so that the
bacteria can be
grown on nutrient
agar.
• A multidisc is placed
on the agar surface.
• It is important to have a choice
of antibiotics because:
– The person may be allergic to an
antibiotic
– Bacteria may become resistant to
an antibiotic
Antibiotic production
• Antibiotics produced in large
fermenters holding 200,00 litres
• Growth conditions are controlled by
computer to provide correct
–
–
–
–
–
Temperature
pH
Oxygen concentrations
Food supply
Sterile conditions
Antibiotic purified by filtering
and solvent extraction
Genetic modification
• Genetic modification is a new
technology.
• It changes the genes found in living
things.
• The penicillin gene can be taken from
the fungus and put into bacteria.
• These ‘genetically modified’ bacteria
can then produce very large quantities
of penicillin.
• New, more effective antibiotics can
also be produced to help fight disease.
Antibiotic production
Activity 4.2
 Antibiotics were first produced in ___________ by
______________ ____________. They are chemicals which
kill ____________. They do not kill _________.
 Antibiotics are produced in huge ____________.
Growth conditions inside the fermenters are
controlled by ____________. If the glucose level in the
vessel falls then the ________ will detect this
_____________and more ____________ will be added. The
antibiotic is _________________ by filtering and
_______________ extraction.
 ______________ modification is a new ______________
which can alter the _____________ of living organisms.
This new technology may be used to produce new
_____________ which will be better at fighting_________
Antibiotic production
Activity 4.2
 Antibiotics were first produced in London by
Alexander Fleming. They are chemicals which kill
bacteria. They do not kill viruses.
 Antibiotics are produced in huge fermenters.
Growth conditions inside the fermenters are
controlled by computers. If the glucose level in the
vessel falls then the computer will detect this
change and more glucose will be added. The
antibiotic is purified by filtering and solvent
extraction.
 Genetic modification is a new technology which can
alter the genes of living organisms. This new
technology may be used to produce new antibiotics
which will be better at fighting disease.
Antibiotic resistance
Some infections have
become resistant to
antibiotics. This means
that the antibiotic is no
longer effective.
Staphylococcus aureus is
a bacteria that causes
abscesses and boils
1940’s this bacterium was
sensitive to penicillin so it
could be used to treat
Staphylococcus aureus
infections.
Now some strains of this bacteria are resistant
to penicillin and it is no longer effective.
These strains have also become resistant to
other antibiotics and are known as MRSA.
These strains are prevalent in hospitals where
infections are easily spread.
This has happened because because
antibiotics have been over-used.
Public concern
• People are concerned about the over-use of
antibiotics in agriculture and by vets.
• The same antibiotics are
used in animals and humans.
• It is thought that this might result in more
resistant strains of bacteria.
• New antibiotics to which bacteria are not
resistant are continually being looked for.
Anti-fungals
• Some infections are
caused by microbes called
fungi
• They are spread from
person to person by tiny
groups of fungi called
spores.
• Drugs used to treat these
infections are called antifungals.
• Anti-fungal treatment
slows down or stops fungal
growth.
Athlete’s foot
• This fungi likes to grow areas
of the skin which are warm and
moist and get little fresh air.
• Forms an itchy rash between
the toes.
• Transferred in shared dressing
areas or showers.
• Flakes of skin from an infected
person are enough to pass the
infection on
• Treated with antifungal creams
or powders.
Oral thrush
• Fungal infection of the
mouth.
• Seen as white spots in the
mouth.
• Common amoung:
–
–
–
–
Babies
People with ill fitting dentures
Chemotherapy patients
Drug users
• Treated with antifungal mouth
washes or pastilles
Ringworm
• Begins as a patch of itchy skin
• Spreads to form spiral shapes
• Caused by a fungus not a worm!