ST NINIAN’S HIGH SCHOOL

INTERMEDIATE 1/ ACCESS 3

BIOLOGY

BIOTECHNOLOGICAL INDUSTRIES

STUDENT SUMMARY NOTES

document.doc

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 UHTpowdered.

Resazurin dye test

2

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 should kill all the harmful bacteria.(Microbes)

The taste of milk is changed by the way it is treated.

document.doc

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 72C for at least 15 seconds.

It is then quickly cooled to a temperature below 10C.

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 135C and 142C for 2 to 5 seconds.

This processing alters the taste of the milk.

Preserves milk and helps it last longer.

3

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.

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 semi-skimmed milk to young children.

1

Semi-skimmed

half of the fat removed. Skimmed milk

almost all the fat removed.

Evaporated milk

half the water taken outused like creamway to preserve milk

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.

2

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.

Monitoring waste

When cheese is made the solid curds go on to form the cheese but the liquid whey is a waste product.

3

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.

4

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.

Beer

5

Around half the beer which is drunk today is lager and the other half is bitter, ale and stout.

In Britain today there are over 1200 different brands of beer. Each brand is different and has its own flavour.

An alcoholic drink made from water, barley, sugar, hops and yeast.

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 - flavourremoves solid material

gives it sparkle

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

6

Different beers are brewed in different ways and they have different alcohol contents.

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.

7

- Often called Real Ale

- Made in casks

- The yeast is not removed

- Fermentation and carbon dioxide production continues in cask.

- for sale in kegs, bottles or cans

- stored in large tanks

- yeast is removed

- carbon dioxide is added.

- this type of beer such as lager is therefore clear and bright and has a longer shelf life than cask beer

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

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.

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.

8

Used to trap an enzyme and some yeast into a jelly bead.

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.

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.

9

3. Detergent Industries

Biological washing powders

The word detergent means

Some washing powders are known as

Biological washing powders contain

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

10

1% enzymeswater softenersbleachchemicals

biological washing powders.

enzymes.

“something which cleans”. Soaps, washing up liquid and washing powder

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

11

been coated to prevent allergic reactions, which can cause skin rashes and eczema.

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 40C and about 55C.

11. The enzymes are destroyed at temperatures above 60C.

12. The lower temperatures used in washing with biological powders are also kinder on clothes as high

temperatures can damage delicate fabrics.

Monitoring waste

12

Energy is used in

production, packaging and transporting of detergents

greatest use of energy is 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. Washing clothes at low temperatures.2. Reduces fuel consumption.3. Contributes to reducing pollution caused by the

burning of fossil fuels in power stations.4. 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.

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.

13

In the home

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.

4. Pharmaceutical Industries

14

There are many different types of antibiotic.

Destroy and prevent the further growth of bacteria.

Produced naturally by fungi from soil

AntibioticsThey were discovered by Alexander Fleming.

Penicillin - most common antibiotic

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.

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.

15

Produced commercially in automated industrial fermenters.

Only act on bacteria and not on viruses.

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.

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.

16

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.

Anti-fungals

Some infections are caused by microbes known as fungi.

Some common fungal infections are

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.

17

athletes footthrush

18