Presentation on theme: "Biotechnology Unit 1 : Dairy Industries i. Milk ii. Yoghurt"— Presentation transcript:
1Biotechnology Unit 1 : Dairy Industries i. Milk ii. Yoghurt iii. Cheeseiv. Environmental Impact
2i. Milk Milk is an important food for most British people. It is an important part of a balanced dietMilk contains:fatstarchsugarproteinminerals
3Milk treatment All milk comes from dairy cows. It is treated in different ways to produce different types.Milk is available in forms such as: pasteurisedskimmedUHT (ultra high temperature)powder
4Heat 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:pasteurisationUltra High Temperature
5Pasteurisation 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 tofive days in a fridge.
6Ultra High Temperature UHT milk is heated to a higher temperature than pasteurised milk.UHT milk is heated to 135oC-142oC for 2-5 seconds.This process alters the taste of milk.
7Resazurin TestResazurin 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.
8Colour of sampleBacterial contentDrinking quality of milkBlue-purpleVery lowGoodmauvelowSatisfactorypinkmediumPoorwhitehighunsatisfactory
9Experiment: resazurin test 5 day old milk + resazurinFresh milk + resazurin10 day old milk + resazurin
11Fat content of milk Milk can be graded by its fat content: Type of milkFat removedWhole milknoneSemi-skimmedhalfskimmedalmost allEvaporated milk has ½ the water removed and is used like cream.
12Content of milk (continued) Removing fat from milk reduces vitamin content e.g. Vitamin ASkimmed and semi-skimmed milk have fat removed so the vitamin content is reduced.Young children should be given whole milk which has more vitamins.
13ii. YoghurtMilk 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.
14Making YoghurtStarter cultures contain special bacteria that make lactic acid from the sugar (lactose) in the milk.lactose lactic acid(sugar in milk) (thickens and gives taste)Lactic acid thickens the milk and gives the yoghurt its taste.
15Making yoghurt Method Heat milk to 43oC (helps bacteria grow) Add 1 teaspoon of starter culture (natural yoghurt)Cover with cling film.Incubate yoghurt at 43oC for 7 hours.When ready, place yoghurt in fridge for 4 hours.
16Types of Yoghurt There are different methods for making yoghurts: Stirred yoghurts – bacteria is added to the batch. It is then put in to pots when ready.Set yoghurts – bacteria is added then the mixture is put straight into the pots where it sets.
17Aseptic 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.
18This is done for two reasons: To stop unwanted microbes getting into the experiment and spoiling itTo stop ant microbes used in the experiment escaping.
191. Hands should be washed, cuts should be covered. 2. Work surfaces should be disenfected.3. Lab coats should be worn4. All equipment should be sterilised in an autoclave (heated to 121C for 20 mins).
20iii. 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.
21Types of rennet Calf rennet calves Fungal rennet fungus Milk clotting enzymes (rennet) can come from different sources.Type of rennetSourceAdvantageDisadvantageCalf rennetcalvesOriginal source, used for centuries.Animals must be killed, risk of diseaseFungal rennetfungusCheap, large amounts, OK for vegetarians.tasteGM yeast rennetyeastNo animals involved, OK for vegetarian, same as animal rennet.Public concern about genetically modified foods
22iv.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 + rennetcurds (solid) whey (liquid)cheese waste product
23Whey and pollutionWhey 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.
24Pollution prevention To prevent pollution whey can be:- a. treated before releaseb. upgraded (used for something else)
25Treatment of wheyAdd 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.
26Upgrading wheyWaste 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)
28Biotechnology Yeast Industries i. Bread ii. Beer iii. Fermented milk drinksiv. Flavouring andfood colouringv. Environmental impact
29i. Bread Yeast: a single-cell fungus (plant) used in bread-making for 1000’s of yearsis added to flour to make bread rise (dried or fresh yeast – activity 2.1)
30Yeast (continued) Yeast is a living organism. It respires to release carbon dioxide.It is the carbon dioxide that makes bread rise.
31Growing yeastHuge 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.
32Beer is an alcoholic drink made from: water ii. BeerBeer is an alcoholic drink made from:waterbarleysugarhopsyeast
34The role of yeast in making beer sugar alcohol + carbon dioxide+ energyYeast 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.yeast
35Ales and lagersDifferent strains of yeast give different ales and lagers.These yeasts use the sugars at different rates and at different temperatures.
36Ale and lager yeasts Type of yeast Growth temp Time to grow Position of yeast in vesselAle12-18ºC6 daysRise to topLager8-12ºC21 daysSink to bottomAle yeasts
37Making beerThere 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)
40Maturing the beer Beer must be matured before it can be drunk. Maturing beer:Improves flavourRemoves any solidsGives ‘sparkle’(activity 2.6)
41Beer can be: cask conditioned brewery conditioned (often called real ale)brewery conditioned(kegs, bottle, cans)
42Cask conditioned beerCask conditioned beer is put into casks (huge containers madefrom 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.
44Brewery conditioned beer Stored in large tanksSold 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)
45Differences : cask conditioned and brewery conditioned beers (Activity 2.6)Cask conditioned beerBrewery conditioned beerExample of type of beer producedStorage conditionsDescription of beer
46Differences : cask conditioned and brewery conditioned beers (Activity 2.6)Cask conditioned beerBrewery conditioned beerExample of type of beer producedReal alee.g. LagerKeg beersBottles/cansStorage conditionsCasksSugar addedYeast presentLarge tanksYeast removedDescription of beerDark colourHigh flavourClear/brightLasts longer
47iii. 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.
48Making 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.
49Making KefirStep 1Sodium alginate + lactase (enzyme that breaks down lactose)Add wine yeastAdd calcium chloridedrop by drop(hardens beads)Immobilised beads
50Step 2 Warm milkAdd live yoghurtAdd Immobilised beadsLeave at 43ºC for 5 hoursFilter mixture to givefermented milk drinkBeads can be re-usedkefir
51ImmobilisationImmobilisation can be used to trap an enzyme and some yeast into a jelly bead.Advantages: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)jelly coatyeast + enzyme
52iv. Food flavouring Yeast can be used for: Making breadAlcoholic drinksFlavouring foodFoods with yeast flavouring:Meat flavoured crisps e.g. chicken,baconOxo cubesMarmite(activity 2.9)
53Food colourings (activity 2.10) Wild salmon and trout have pink flesh.This colour comes fromthe pink coloured prawnsand 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
54Feeding 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
55v. Environmental Impact Waste from yeast industries should not be dumped in rivers.Yeast would act as food for bacteria which would cause pollution.
56Getting rid of waste Waste can be upgraded and used for animal feed. Treated water shouldbe tested beforereleasing into rivers.
57The 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 C3specimen tubes+lids3 labelsdroppermeasuring cylindermethylene blue dye
58Testing water samples for pollution: The Methylene Blue Test TimeColour changeWater conditionPollution scaleImmediate2-3 days4-5 days
59The methylene blue test TimeColour changeWater conditionPollution scaleImmediateBlue to clearDangerous for riverVery polluted2-3 days4-5 daysNeeds more treatmentSlightly pollutedStill blueSafe for releaseNot polluted
61Enzymes in washing powders The word detergent means ‘something that cleans’ e.g.soapswashing up liquidwashing powder
62Biological washing powders Biological washing powders contain enzymes.Enzymes are chemicals that improve the way in which the powder cleans.
63What is biological washing powder made of? Biological washing powder is made up of:1% enzymes99% water softenersbleachother chemicals (to help water get into the clothes)
64Where 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.
65The 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 small part of powderbut a large part of the cleaning power!
66Activity 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.In the following experiment, enzymes like those in biological washing powder are used to remove the ‘stain’ on a piece of photographic filmProtein ‘stain’
67Expt. : To investigate the effect of enzymes on a protein stain Method:Collect 2 test tubes.Label test tubes A and BAdd 1 piece of film to each test tube.Half fill tube A with enzymeHalf fill tube B with waterShake each tubePut tubes in water bath at 50oC for 30 mins – shake tubes every 5 minsRemove film, dry and examine.
68Tube contentsProtein digested?Film + EnzymeFilm + water
69Comparing biological and non-biological 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
70Comparing bio and non-bio washing powders Warm water + bio powderWarm water +non- bio powderStained clothStained cloth
71StainRemoved with bio powder?Removed with non-bio powder?
72Disadvantage 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)
73Advantages of biological washing powders (Activity 3.4) 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.
74Environmental Impact : Monitoring Waste Making detergent uses energy for:ProductionPackagingTransportingBut most energy is used in the home for:The wash cycleTumble dryingIroning
75Detergents and energy Activity 3.5 To provide all the energyneeded power stations burncoal, oil or gas.This gives off carbon dioxideand sulphur dioxide thatpollute the atmosphere.Low temperature wash = less energy good for public and environment!!
76One manufacturer of detergents has set targets for waste management: Reduce weight and volume of packingUse reusable materialsEncourage recycling programmesEncourage safe disposal practisesNew ‘Micro’ powders and liquids use less packaging and powder for each wash.
77Detergents 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.
78Detergents containing phosphates and sulphates pollute river Tiny plants (algae) reproduce quickly to form ‘bloom’Algae dieBacteria feed on dead algaeNumber of bacteria increasesBacteria use up oxygen in waterFish and animals die
79Reducing Environmental Impact Detergents in water tested at sewage works in mini sewage plantsSewage plants could remove the phosphates and sulphates to reduce environmental impactUsing low phosphate detergents can also reduce environmental impact
80Washing clothes in other countries (Activity 3.7) Most people in the worldwash clothes by handWashing machines in other countries are different from those in the UKIn the USA washing machinesare bigger and use more waterIn Japan and Taiwan washing machines do not heat the water. Clothes are pre-soaked and washed more often
81Biotechnology Unit 4 : Pharmaceutical Industries i. Antibiotics ii. Antifungals
82Antibiotics~ 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
83~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.
85Other 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.
86~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
87Antibiotic actionIf an antibiotic can inhibit growth of a species of bacteria we say the bacteria is sensitive to that antibioticIf 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
88+ + + - + + + Antibiotic + + + = very effective + + = effective PneumoniaTuberculosisTyphoidDiptheriapenicillin+ + +-StreptomycinTetracycline++ +Cloram-phenical= very effective= effective= slightly effective= no effect
89Different antibiotics have different methods of destroying bacteria: Some destroy bacterial cell wallsSome burst the cell membraneSome interfere with the bacterial cell’s chemical reactions
90Different types of antibiotics (Activity 4.3) Different antibiotics are effective against different infections.AntibioticInfection which it treatspenicillinrespiratory infections (and many others)aminoglycosidesEye and skin infectionsfluoroquinilesGonorrhoea (STD)cephalosporincUrinary infectionstetracyclinesacne
91Choosing 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.
92It is important to have a choice of antibiotics because: The person may be allergic to an antibioticBacteria may become resistant to an antibiotic
93Antibiotic production Antibiotics produced in large fermenters holding 200,00 litresGrowth conditions are controlled by computer to provide correctTemperaturepHOxygen concentrationsFood supplySterile conditionsAntibiotic purified by filteringand solvent extraction
94Genetic 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.
95Antibiotic production Activity 4.2Antibiotics 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_________
96Antibiotic production Activity 4.2Antibiotics 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.
97Antibiotic 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 boils1940’s this bacterium was sensitive to penicillin so it could be used to treat Staphylococcus aureus infections.
98Now 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.
99Public concernPeople are concerned about the over-use of antibiotics in agriculture and by vets.The same antibiotics areused 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.
100Anti-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 anti-fungals.Anti-fungal treatment slows down or stops fungal growth.
101Athlete’s footThis 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 onTreated with antifungal creams or powders.
102Oral thrush Fungal infection of the mouth. Seen as white spots in the mouth.Common amoung:BabiesPeople with ill fitting denturesChemotherapy patientsDrug usersTreated with antifungal mouth washes or pastilles
103Ringworm Begins as a patch of itchy skin Spreads to form spiral shapes Caused by a fungus not a worm!