Biotechnology

Question 1

What is biotechnology

Answer 1

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

Question 2

What is the most commonly used organism in biotechnology processes?

Answer 2

Fungi, yeast, bacteria.

Question 3

Why are microorganisms ideal to use?

Answer 3

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

Question 4

How are microorganisms involved in baking

Answer 4

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.

Question 5

How is microorganisms used for brewing?

Answer 5

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.

Question 6

How are microorganisms used for cheese making

Answer 6

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

Question 7

Role of bacteria in yoghurt production

Answer 7

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.

Question 8

What is SCP

Answer 8

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

Question 9

How does Quorn make protein from fungus

Answer 9

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.

Question 10

Advantages of using microorganisms to make food directly for consumption

Answer 10

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

Question 11

Disadvantages of using microorganisms to produce human food?

Answer 11

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

Question 12

What was penicillin produced by, and when did it become large scale

Answer 12

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

Question 13

What are the stages of penicillin creation from P. Chrysogenum?

Answer 13

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

Question 14

What are the conditions for penicillin

Answer 14

- 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

Question 15

What do those with type 1 diabetes need

Answer 15

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

Question 16

What overcame the problems of animal insulin?

Answer 16

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

Question 17

What is bioremediation

Answer 17

Using microorganisms to Break down pollutants and contaminants in the soil or water

Question 18

How can we use natural organism to carry out bioremediation

Answer 18

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.

Question 19

How are gm organisms used for bioremediation

Answer 19

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

Question 20

What are risks of culturing microorganisms

Answer 20

There is a risk of mutation occurring - making the strain pathogenic

There may be contamination with pathogenic microorganisms from the environment

Question 21

What do microorganisms need to grow and be cultured in a lab

Answer 21

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

Question 22

How to inoculate nutrient broth?

Answer 22

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

Question 23

How to inoculate agar

Answer 23

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

Question 24

What are the 4 stages of bacterial growth?

Answer 24

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

Question 25

What are some limiting factors of a culture of bacteria

Answer 25

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

Question 26

What are Primary and secondary metabolites

Answer 26

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

Question 27

How does batch fermentation work (industrial culture of microorganisms)

Answer 27

- 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

Question 28

How to grow microorganisms with continuous culture

Answer 28

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.