Biotechnology Flashcards
What is biotechnology?
The industrial use of living organisms (or parts of living organisms) to produce food, drugs or other products
What are the main advantages of using microorganisms in biological processes?
- No ethical issues when growing
- Large variety of microorganisms
- Genetically modified to produce protein required
- Short life cycle & rapid growth rate - huge quantities can be produced in short periods of time
- Cheap
What microorganism is involved in baking?
- Yeast: mixed with sugar and water to respire aerobically
- CO2 produced makes bread rise
- Yeast cells are killed during cooking
- Takes a couple hours
What microorganism is involved in brewing?
- Yeast: respires anaerobically to produce ethanol
- Mixed with malted barley and hot water
- Fermentation continues for days in anaerobic conditions
What conditions are needed to make bread rise?
- Oxygen
- Heat
- Carbohydrates (flour)
What microorganisms are involved in cheese making?
- Bacteria: feed on lactose in milk, changing texture and taste, and inhibiting the growth of bacteria which makes the milk go off
What microorganisms are involved in yoghurt-making?
- Bacteria: to form ethanol and lactic acid
- Both produce extracellular polymers that give yoghurt its smooth, thick texture
Why is milk pasteurised before being used commercially to make cheese and yoghurt?
- To kill of most natural bacteria that would make it go bad rapidly
- This is done by heating it for a certain amount of time.
Why is milk homogenised before being used commercially to make cheese and yoghurt?
- To allow the fat droplets to evenly distribute through the milk
- This will make the final product smoother and with less fat content
Give 2 differences between the production processes of cheese and yoghurt
- The milk is heated in cheese making and cooled in yoghurt making
- Whole milk is used in cheese making and skimmed milk is used in yoghurt making
Give 4 advantages of using microorganisms to produce human food?
1- Microorganisms reproduce fast and produce protein faster than animals and plants
2- They have high protein content with little fat
3- No welfare issues when growing microorganisms
4- Can be made to taste like anything
Give 4 disadvantages of using microorganisms to produce human food
1- Need sterile conditions that are carefully controlled which adds to cost
2- Protein has to be purified to ensure it contains no toxin or contaminants
3- Many dislike the thought of eating microorganisms grown on waste
4- Has little natural flavour - needs additives
Producing penicillin
- Needs relatively high oxygen levels and a rich nutrient medium to grow well
- It is sensitive to pH and temperature
- A semi-continuous batch process is used
- First stage = fungus grows
- Second stage = produces penicillin
- Drug is extracted from medium and purified
Key points about producing penicillin
- Small fermenters (40-200dm3) as it’s difficult to maintain high levels of oxygenation in large ones
- mixture is continuously stirred to keep it oxygenated
- Rich nutrient medium
- Growth medium contains a buffer to maintain pH at around 6.5
- Bioreactors are maintained at about 25-27°C
What is bioremediation?
Where microorganisms are used to break down pollutants and contaminants in the soil or water
What are the different approaches to bioremediation?
- Using natural organisms: many microorganisms naturally break down organic materials producing CO2 and water
- GM organisms: scientists are trying to develop GM bacteria which can break down or accumulate contaminants which they would not naturally encounter
What are the requirements for optimal growth when culturing microorganisms in the lab?
- Optimum temperature
- Optimum pH
- Oxygen (unless anaerobic)
- Food (nutrient medium)
- Aseptic technique conditions
How do you grow a broth culture?
- Mix sterile nutrient medium with water to make broth
- Mix known mass of dried bacterial culture with water to make suspension
- Inoculate the sterile broth with a known volume of the bacterial suspension
- Stopper the flask, with cotton wool or a bing with air inlet, to prevent contamination from the air
- Incubate at suitable temperature, shaking regularly to aerate