BIOTECHNOLOGY Flashcards
Biotechnology
Industrial use of living organisms to produce food, drugs and other products
Why are microorganisms used
Ideal growth conditions are easily created
Short life cycle- grow rapidly under the right conditions
Economic- uses waste material
Grown anytime of the year
Single celled protein
Cultured anywhere with the right equipment
Microorganism uses
Brewing- yeast added to a grain, yeast respires anaerobically and produces ethanol and CO2 (fermentation)
Baking- yeast makes bread rise- CO2 produced
Cheese making- uses rennet, rennet contains the enzyme chymosin which clots the milk, uses lactic acid bacteria which convert lactose in milk to lactic acid
Yogurt production- involved lactic acid bacteria
Penicillin production- fungi make penicillin to stop the bacteria from growing and competing for resources, the fungus is grown in an industrial fermentator
Insulin production- genetically modified bacteria which have the gene for human insulin production inserted into their DNA
Bioremediation- using organisms to remove pollutants from contaminated sites
Disadvantages of using microorganisms
Effort to avoid contamination
Waste products to grow food seems unattractive
Doesn’t have same texture and flavour as meet
Consumed in high quantities leads to health problems because high levels of uric acid is produced when amino acids are broken down
Culture
A population of just one type of microorganism that has been grown in controlled conditions
Batch fermentation
Microorganisms grown in individual batches in a fermentation vessel
When one culture is produced it’s removed and a different batch of microorganisms is grown in the vessel
Closed culture
Continuous fermentation
Microorganisms continually grown in a fermentation vessel without stopping
Nutrients put in and waste products are taken out at a constant rate
Conditions in vessels are kept at optimum for growth which maximises the yield of microorganisms and desirable products
Optimum conditions in continuous fermentation
pH- monitored and kept at optimum level allowing enzymes to work efficiently so the rate of reaction is kept as high as possible
Temperature- kept constant by a water jacket, allows enzymes to work efficiently
Access to nutrients- paddles constantly circulate fresh nutrient medium around the vessel which ensures that the microorganisms always have access to their required nutrients
Volume of oxygen- sterile air pumped into the vessel when needed which makes sure that microorganisms always have oxygen for respiration
Vessel kept sterile- superheated steam sterilises the vessel after each use which kills any unwanted organisms that may compete with the ones being cultured
Closed culture
Growth takes place in a vessel that’s isolated from the external environment and extra nutrients aren’t added and waste isn’t removed
Standard growth curve
- LAG PHASE- population size increases slowly because the microorganisms have to make enzymes and other molecules before they reproduce this means the production rate is slow
- EXPONENTIAL PHASE- population size increases quickly because the culture conditions are at their most favourable for production and the number of microorganisms doubles at regular intervals
- STATIONARY PHASE- population stays level because the death rate of microorganisms equals their reproductive rate. Microorganisms die because there isn’t enough food and poisonous waste products build up
- DECLINE PHASE- population size falls because the death rate is greater than the reproductive rate this is because food is scarce and waste products are at toxic levels
Culturing microorganisms in the lab
Agar plate- agar jelly in a Petri dish
Microorganisms are transferred to the plate from a sample using a sterile implement e.g an inoculation loop
Plates are then incubated to allow microorganisms to grow
Nutrients added to the agar plate to improve the growing conditions
Aseptic techniques
Prevents any contamination of any unwanted microorganisms being cultured
Contamination- imprecise results and may be hazardous to health and on an industrial scale can be costly
Regularly disinfect workspace
Work near Bunsen flame- hot air rises so microorganisms will be drawn away
Sterilise instrument before and after each use
Pass the neck of the container through a Bunsen flame after its open and closed
Minimise time the agar plate is open and place lid on as soon as possible
Sterilise all glassware before and after use
Wear a lab coat, gloves and tie hair back
Investigating factors affecting the growth of microorganisms
Growing microorganisms on agar plates under different conditions
Measure growth of microorganisms directly in broth using a spectrophotometer which measure the turbidity of the broth
Why are immobilised enzymes used
Isolated enzymes in industry can be mixed with products in a reaction the products can then be separated which could be costly and complex
This is avoided by using immobilised enzymes because they are attached to an insoluble material so the can’t be mixed with the products
3 ways to immobilise an enzyme
Encapsulate in jelly alginate beads which act as a semi permeable membrane
Trapped in a silica gel matrix
Covalently bonded to cellulose or collagen fibres
