Biotechnology Flashcards
What is biotechnology
the industrial use of living organisms, or parts of living organisms, to produce food, drugs or other products for the service of people. This includes things like cheese production or bread, to DNA manipulation to produce genetically engineered microorganisms to synthesise drugs like insulin. Also bioremediation to remove water pollution
What is the most commonly used organism in biotechnology processes?
Fungi, yeast, bacteria.
Why are microorganisms ideal to use?
No welfare issues - all they need is optimum growth conditions
Lots of different microorganisms that can be used to carry out many different chemical synthesis or degradations
Can artificially Manipulate microorganisms to carry out synthesis reactions that we could not do naturally as humans. For example to produce insulin
Short life cycle and rapid growth rate. Huge quantities of ba tiers can be grown in very short amounts of time
Can engineer bacteria to use our waste materials. So they are cheap to sustain and useful materials can be used elsewhere for other industrial processes
Conditions are not quite easy to keep. Low temps, oxygen and food. This makes them very cheap
How are microorganisms involved in baking
The active yeast mixture is added to flour and other ingredients. Mixed and left in
warm environment to rise.
Dough is knocked back (excess air removed), kneaded, shaped, and left to rise again.
Cooked in a hot oven - the carbon dioxide bubbles expand, so the bread rises more.
Yeast cells are killed during cooking.
How is microorganisms used for brewing?
To make beer, yeast is added to a type of grain such as barley and other ingredients.
The yeast respires anaerobically using the glucose from the grain and produces ethanol (alcohol) and CO2.
When anaerobic respiration produces ethanol, it is called fermentation.
They ferment at 20-28°C, clumping together and sinking to the bottom at the end of the process, leaving the beer clear.
How are microorganisms used for cheese making
Pasteurised milk is used as a raw material
Bacteria are used to digest lactose, producing lactic acid
Lactic acid lowers the pH of the milk
The low pH causes proteins in the milk to denature, leading to separation of curds (solids) and whey (liquids)
Curds are pressed and processed into hard cheeses
Mould spores from saprotrophic fungi such as can be artificially introduced into blue-veined cheeses
Role of bacteria in yoghurt production
Yoghurt involves the use of lactic acid bacteria to clot the pasteurised milk by turning it into lactose and cause it to thicken. This creates a basic yoghurt and then flavours and colours are added.
What is SCP
Single cell protein - due to protein shortages, scientists are trying to develop more ways of using microorganisms to directly produce protein you can eat, especially with fungi
How does Quorn make protein from fungus
A single called fungus gets grown in large fermenters using glucose syrup for food. These microorganisms are then combined with albumen (egg whites) and then then compressed and formed into a meat substitute That is high in protein and low in fat.
Advantages of using microorganisms to make food directly for consumption
They produce protein sources faster than animals or plants
High protein and little fat
Microorganisms can live off waste, reducing costs
They can be genetically modified to make the protein required
Takes place constantly, needs no breeding cycles etc
No welfare or ethical issues
Disadvantages of using microorganisms to produce human food?
Microorganisms can produce toxins if conditions not maintained
Need sterile conditions that are always controlled adding to the cost
Concerns involving and eating GM food
Protein has to be purified before eating so it has no contaminants
Many dislike the idea of eating food grown on waste
No natural flavour, needs lots of additives
What was penicillin produced by, and when did it become large scale
A mould called penicillium notatum. But this would produce small yields. Commercial production only came about until the discovery of penicillium chrysogenum on a melon from a market stool
What are the stages of penicillin creation from P. Chrysogenum?
In the first stage - the fungus is grown
In the second stage - it produces penicillin
Third stage - the drug gets extracted from the medium and purified
What are the conditions for penicillin
- Small fermenters around 40-200dm3 as it it hard to maintain high levels of oxygenation in large bioreactors.
- mixture has to be always stirred to keep oxygenated
- has to have rich nutrient medium
- medium has a buffer to maintain pH at around 6.5
- Bioreactors are maintained at about 25-27°C
What do those with type 1 diabetes need
Regular insulin injections. This insulin was often retrieved from the pancreas of animals, usually pigs or cattle that get slaughtered for meat. This insulin could cause allergic reactions and also the supply was erratic due to the demand for meat. The peak activity of animal insulin is several hours after it is injected, which made calculating when to eat meals difficult. And some religions forbid thr use of pig products
What overcame the problems of animal insulin?
The development of genetically modified bacteria to produce insulin - the bacteria would be grown in a fermenter and downstream processing results in a constant supply of pure human insulin
What is bioremediation
Using microorganisms to Break down pollutants and contaminants in the soil or water
How can we use natural organism to carry out bioremediation
Using natural organisms - many microorganisms naturally break down organic material producing carbon dioxide and water. Soil and water pollutants are often biological, for example, sewage and crude oil. If these naturally occurring microorganisms are supported, they will break down and neutralise many
contaminants. For example, in an oil spill, nutrients can be added
to the water to encourage microbial growth, and the oil can be
dispersed into smaller particles to give the maximum surtace area
for microbial action.
How are gm organisms used for bioremediation
Scientist have attempted to create bacteria that can break down or accumulate contaminates which they would not naturally encounter. I,e, bacteria has been modified to remove mercury from contaminated water.mercury is very toxic and can affect food chains
What are risks of culturing microorganisms
There is a risk of mutation occurring - making the strain pathogenic
There may be contamination with pathogenic microorganisms from the environment
What do microorganisms need to grow and be cultured in a lab
They need food and this is provided in the form of a nutrient medium. This can be solid or liquid form. Only few need specific nutrients but often the medium is simply enriched with good protein sources like blood or yeast extract or meat. This allows a very small culture to multiply rapidly. This medium must also be kept sterile through aseptic techniques
How to inoculate nutrient broth?
Make a suspension of the bacteria to be grown
Mix a known volume with the sterile nutrient broth in the flask
Stopper the flask with cotton wool to prevent contamination from the air.
Incubate at a suitable temperature, shaking regularly to aerate the broth providing oxygen fro the growing bacteria
How to inoculate agar
1) Wire inoculating loop must be sterilised by holding it in a Bunsen flame until glowing red hot.
2) Dip the sterilised loop in the bacterial suspension then remove the lid of the Petri dish and make a zig zag streak across the surface of the agar. Avoid digging into the agar by keeping it fully horizontal.
3) replace lid of Petri dish. It should be held down with tape but not sealed completely so oxygen can get in, preventing bacteria to anaerobically grow. Then incubate at a suitable temperature
What are the 4 stages of bacterial growth?
Lag phase - bacteria are adapting to their new environment. They are growing, synthesising enzymes that they need and not reproducing at their maximum weight
Exponential phase - rate of bacterial reproduction is close to its theoretical max
Stationary phase - when total growth rate is zero as the number of new cells formed by binary fission is cancelled out by the number of cells dying
Death phase - reproduction has ceased and the death rate of cells increases
What are some limiting factors of a culture of bacteria
Nutrient availability - initially there is plenty of food, but as they multiply, these nutrients get used up and the nutrient level will be insufficient to support further growth and reproduction unless more nutrients are added
Oxygen levels - as population rises so does the demand for respiratory oxygen so this can be a limiting factor
Temperature - enzyme controlled reactions within the bacteria are affected by temp. Low temps slow growth whereas high temps speed it up, but too high will denature the enzymes.
Waste - as colonies grow, the amount of waste they release may inhibit growth
pH - increased carbon dioxide causes pH to fall until it reaches a point that inhibits population growth
What are Primary and secondary metabolites
Primary metabolites are Resources that are essential for the proper growth of microorganisms
Secondary metabolites are formed when the microorganisms are not growing and dividing rapidly. I.e. during stationary phase
How does batch fermentation work (industrial culture of microorganisms)
- The microorganisms are inoculated into a fixed volume or medium
- as growth occurs, nutrients are used up and both new biomass and waste products build up
- once culture reaches stationary phase, overall growth ceases, but during this phase the microorganisms often carry out biochemical changes to form the desired end products
- this process is stopped before the death phase and the products are harvested. The whole system is cleaned and a new batch culture is restarted
How to grow microorganisms with continuous culture
Microorganisms are inoculated into a sterile nutrient medium and they start to grow
Sterile nutrient medium is added continually to the culture once it reaches an exponential point of growth
Culture broth is continually removed - the medium, waste products, microorganisms and product - keeping the culture volume constant
This allows for balanced growth.
