Problems and profit with waste. Standard Grade Biology Biotechnology

Transcription

1 Problems and profit with waste Standard Grade Biology Biotechnology

2 Learning Outcomes Describe some examples of the damage caused to the environment by disposal of untreated sewage. Give examples of diseases which may be spread by untreated sewage.

3 Untreated Sewage Untreated sewage contains Organic material Mineral salts Bacteria Some of these can cause disease Untreated sewage can have biological and chemical effects on a river Biosphere revision / indicators of pollution

4 Effect of untreated sewage on a river Complete the diagram with labels untreated sewage bacteria release nitrates and phosphates anaerobic bacteria releases methane and ammonia gases foul smelling gases and rotting material float to surface animals die from lack of oxygen bacteria respire using up the oxygen algal bloom (forms a thick mat) bacteria feed on raw sewage

5 Effect of untreated sewage on a river

6 Water-borne diseases Untreated sewage contains microorganisms which can cause disease Dysentery Typhoid Cholera Disease is prevented by keeping sewage separate from drinking water.

7 Risk of water-borne diseases Contamination of drinking water may occur after Earthquakes (pipes fracture) Flooding Boiling water reduces risk of contamination

8 Learning Outcomes Describe the principal precautions to be taken during laboratory work with microorganisms. Explain the precautions which are taken during manufacturing processes with reference to resistant fungal and bacterial spores. Explain the importance of such precautions in biotechnological processes whenever relevant.

9 Airborne disease The air contains Dust Fungal spores Bacteria (and spores)

10 Sterile Techniques Surfaces are wiped with disinfectant Glassware is treated in an autoclave Agar plates are prepared to ensure agar is sterile at the start of the experiment

11 Culturing microorganisms Sterile techniques are used to avoid contamination with unwanted microbes

12 Preparing a bacterial culture

13 Summary of precautions

14 Resistant Spores Bacterial cells protect themselves from unfavourable conditions by forming endospores. Endospores are resistant to Extreme temperatures Drying out ph changes disinfectants

15 Sterile technique summary Write out each technique and write out why each stage is necessary Heating glassware in an autoclave Holding lid over open petri dish Flaming wire loop Flaming the mouth of the culture tube Applying tape to the plates

16 Learning Outcomes Describe the part played by bacteria in the process of decay and recycling of carbon and nitrogen. Explain the process of decay in terms of the energy requirements of microorganisms.

17 Decay Decomposers are Bacteria Fungi They decompose organic substances in order to obtain the energy and materials they need to survive.

18 Nutrient cycling Nutrients in environment decomposers decomposition producers consumers

19 The carbon cycle Carbon dioxide In the air (CO 2 ) photosynthesis respiration Combustion (burning) feeding Fossil fuels Coal, oil, gas, peat Carbon compounds in plants Carbon compounds in animals decay

20 saprophytes Organisms which obtain it s food from dead or decaying organic matter. Enzymes are secreted onto the food for external digestion before being absorbed. Mineral salts present in the organic matter are released into the soil and are recycled.

21 Nitrogen Cycle

22 The Nitrogen Cycle Plants and animals need nitrogen to make proteins. Nitrogen gas is unreactive and can not be used by living things Nitrogen gas must be changed to nitrates before it can be used by plants. Animals then eat plants

23 The Nitrogen Cycle Nitrogen gas in air (N 2 ) Proteins in animals Proteins in Plants Dead bodies or waste material Ammonium compounds (NH 4 ) Nitrites in soil (NO 2- ) Nitrates in soil (NO 3 )

24 The nitrogen cycle Denitrifying bacteria Nitrogen gas in the air Nitrogen fixation Animal protein Plant protein Animal wastes Decay bacteria break down proteins and release ammonia Nitrogen fixing bacteria in the soil Nitrogen fixing bacteria in root nodules Nitrifying bacteria Nitrates in soil

25 Nitrogen fixation Making nitrates from the nitrogen gas in the air Nitrogen-fixing bacteria (Rhizobium) found in the soil and in the root nodules of leguminous plants, such as peas, beans and clover

26 Nitrogen Fixation

27 Feeding

28 Decay Nitrogen compounds in living things are returned to the soil as ammonium compounds through: excretion and egestion by animals the breakdown of dead plants and animals by saprophytic (decay) bacteria

29 Nitrifying bacteria Change ammonium compounds to nitrates Ammonium compounds Nitrites Nitrates Nitrosomonas Nitrobacter

30 decay

31 decay

32 Denitrifying bacteria Denitrifying bacteria (Pseudomonas denitrificans) live in water logged soils (anaerobic conditions) They change nitrates back into nitrogen gas.

33 denitrification

34 The bacteria The nitrogen cycle involves four different types of bacteria Saprophytic bacteria Nitrifying Nitrosomonas and Nitrobacter Denitrifying Pseudomonas denitrificans Nitrogen-fixing - Rhizobium In an exam, you will need to be able to describe the roles of these bacteria

35 Leaching Some nitrates may be washed out of the soil by rainwater, this is called leaching. Leaching can lead to the eutrophication of lakes

36 Decay Summary Decay is the breakdown of dead organisms and waste by microbes (bacteria and fungi) Allows the recycling of nutrients Decaying material provides a source of energy for decomposers

37 Carbon Cycle Summary CO 2 in air photosynthesis C Compounds in plants C Compounds in animals C Compounds in dead organisms Fossils feeding respiration respiration Respiration by decomposers Burning of fossil fuels

38 Nitrogen Cycle Key Microbial Processes Nitrogen Fixation Bacteria in root nodules convert nitrogen to nitrate Decay Decomposers (bacteria and fungi) breakdown nitrogen compounds into ammonium compounds Nitrification Bacteria convert ammonium compounds to nitrites Bacteria convert nitrites to nitrates Denitrification Bacteria convert nitrates to nitrogen gas

39 Learning Outcomes State that the main process in the treatment of sewage is its breakdown by the action of decay micro-organisms to products harmless to the environment. Explain why complete breakdown of sewage is only possible in aerobic conditions. Describe how the oxygen required by microorganisms can be provided during sewage treatment. Explain why a range of microorganisms is needed to break down the range of materials in sewage.

40 Sewage Sewage is organic waste from humans Primary treatment of sewage Screening Grit removal Primary settlement

41 Secondary Treatment Oxygen is provided to create aerobic conditions so that bacteria Grow faster Are more efficient Breakdown the sewage completely Two methods Biological filtration Sewage is sprayed onto stone beds Activated sludge process Compressed air is forced through sewage

42 Sludge The suspended matter in the purified sewage settles out as activated sludge The liquid is now effluent The effluent is released into the river The sludge is treated Methane gas is produced Left over solids go to landfill or sea disposal

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45 Why are a range of microorganisms needed To ensure complete breakdown of sewage into carbon dioxide, water and inorganic substances High concentrations of nitrates could lead to an algal bloom in the river so bacteria are used to remove excess nitrates, phosphates and ammonium compounds. The aim of sewage treatment is to reduce the chemical oxygen demand (COD) of the river to the lowest level possible.

46 Learning outcomes Give 2 examples of useful products and the waste materials from which they are gained through the action of micro-organisms and explain the economic importance of this technology. Explain the advantages of upgrading waste in terms of increasing its available energy or protein levels.

47 Upgrading Waste Upgrading waste converts waste products to useful products with a higher economical value. Upgrading by micro-organisms High energy source e.g. methane Rich protein source e.g. Mycoprotein Advantages Reduces environmental pollution Economic saving on waste disposal

48 Examples industry Cheese making Gas and oil Potato crisps Waste product whey methanol Micro-organism used in upgrading yeast Methylophillus (bacterium) Useful product Protein (cattle feed) vitamins Protein (animal feed) starch Fusarium mycoprotein

49 Learning outcomes State that alcohol and methane are products of fermentation. Explain the advantages of deriving fuel through fermentation rather than from fossil sources.

50 Fuels Methane Micro-organisms carry out anaerobic fermentation on manure producing methane gas Gas is used for heat and electricity Alcohol Fermentation of sugar by yeast produces alcohol Alcohol is separated from mixture by distillation Used as a fuel

51 Fuels Fuels from sugars (Brazil) Sugar cane is grown and fermented into alcohol This mixed with petrol produces gasohol which can be used to run cars Fermentation of plant material provides a renewable source of fuels Fossil fuels are non-renewable resources

52 Learning Outcomes State that under suitable conditions, micro-organisms can reproduce very rapidly by asexual means. State that micro-organisms may be harvested to provide protein rich food for animals or man.

53 Growth rate of micro-organisms A bacterium divides asexually by dividing into two. Suitable conditions Optimum ph Optimum temperature Supply of food and water Unlimited growth can occur under ideal conditions

54 Growth of bacteria Use the data to plot a line graph of bacterial growth Describe the shape of the curve produced Time of 24-hour clock Number of bacteria

55 Using micro-organisms Single-celled protein A high percentage of a bacterial cells mass is protein. Bacterial cells are grown, harvested and dried to form a powder called single-celled protein (SCP) Used to feed chicken and calves Single-celled fuels Strains of yeast produce a rich supply of oil This would be suitable for human consumption