Biology Int 1 Acc3 Biotech Ind Summary Notes
ST NINIAN’S HIGH SCHOOL
intermediate 1/ Access 3
biology
biotechnological industries
student summary notes
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Biology Int 1 Acc3 Biotech Ind Summary Notes
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 skimmedUHTpowdered.
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 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.
Milk can also be graded by its fat content so that we can buy
Semi-skimmedskimmed 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.
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.
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.
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.
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
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
In beer making yeast converts sugar into alcohol and carbon dioxide. This process is called fermentation.
The beer is
Cask conditioned beerBrewery conditioned beer
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
- Can be used to make kefir.
- After the reaction the beads can be washed and reused. This saves money because the enzymes can be very expensive.
- The bead can be easily separated from the product.
- 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.
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.
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
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.
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
- 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
- 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.
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.
4.Pharmaceutical Industries
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.
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.
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.
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