Biotechnology

Question 1

What is biotechnology?

Answer 1

Technology based on biology involving the exploitation of living organisms or biological processes to improve agriculture, food science, medicine and industry.

Question 2

What are the 4 main areas that use biotechnology?

Answer 2

1. Healthcare and medicine.
2. Agriculture.
3. Industry.
4. Food science.

Question 3

What does biotechnology in medicine involve?

Answer 3

• Production of drugs.

- Genetic engineering to treat genetic disorders.

Question 4

What are examples if biotechnology in medicine?

Answer 4

• Fungus Penicillium cultured industrially to produce penicillin.
• Bacteria (E. Coli) have been genetically engineered to produce human insulin to treat type 1 diabetes.
• Stem cell technology may used to treat a number of different human diseases.
• Genetic engineering may be used to treat a number of different genetic diseases.

Question 5

What does biotechnology in agriculture in involve?

Answer 5

• Use of biotechnology to improve crop yield.

- Use of biotechnology to improve animal husbandry and animal production.

Question 6

What are examples of biotechnology in agriculture?

Answer 6

• Use of micropropagation to clone plants with desirable traits and improve yield.
• Use of genetic engineering to give plants desirable traits (e.g. Golden rice).
• Use of cloning and IVF to clone animals with desirable traits.
• Use of genetic engineering to give animals desirable traits (e.g. Xenotransplantation and production of pharmaceutical products).

Question 7

What does biotechnology in industry involve?

Answer 7

• Using bacteria to produce enzymes and chemicals.

- Use of genetically engineered bacteria to produce chemicals.

Question 8

What are examples of biotechnology in industry?

Answer 8

• Fungus A. niger produce and secrete enzyme pectinase, which is vital in juice production.
• A. niger also produces citric acid, which is also used a lot in industry, especially in the food industry.
• Methanogenic bacteria can be used to convert sewage into biofuel.
• Bacteria can be used to breakdown waste in sewage during water treatment.

Question 9

What does biotechnology in food science involve?

Answer 9

• Use of biological organisms in the production of food.

- Use of biotechnology to improve the taste, texture, appearance or nutrition value of food.

Question 10

What are examples of biotechnology in food science?

Answer 10

• Lactobacillus acts differently on milk depending on different conditions and is used in yoghurt and cheese production.
• Fungus Fusarium used in the production of Quorn.

Question 11

Why are microorganisms often used in biotechnology?

Answer 11

• Microorganisms grow very rapidly when conditions are optimum.
• Often secrete many proteins or other chemicals into surrounding where they can be easily collected.
• Can be easily genetically engineered as have relatively simple genomes.
• Can grow regardless of time of year/climate.
• Can grow at relatively low temperatures compared to common chemical processes.
• Products generated are purer than synthetic processes.
• Can grow on and recycle waste/toxic materials.

Question 12

What is a culture?

Answer 12

Populations of microorganism/s grown under controlled conditions.

Question 13

What are the stages in a standard growth curve of microorganisms in a closed culture?

Answer 13

1. Lag phase.
2. Exponential (log) phase.
3. Stationary phase.
4. Death phase.

Question 14

What occurs during the lag phase?

Answer 14

• Microorganisms are acclimatising to environment.
• They are carrying out a number of processes before reproduction including:
  1. Rehydrating.
  2. Growing.
  3. Synthesising necessary enzymes.
  4 synthesising organelles.
• Majority of cells not reproducing, so population size remains fairly constant.

Question 15

What occurs during the exponential phase?

Answer 15

• Conditions are optimum and there’s plenty of space and nutrients.
• Cells are reproducing very rapidly.
• Population doubles every generation. Length of time between each generation dependent on organism.

Question 16

What occurs during the stationary phase?

Answer 16

• Space and nutrient levels decrease.
• Competition increases.
• Toxic waste products also build up (e.g. CO2).
• Rate of increases and becomes equal to rate of reproduction, so population size remains stationary.

Question 17

What occurs during death phase?

Answer 17

• Space and nutrient levels continue to decrease.
• Competition continues to increase.
• Toxic metabolites continue to increase.
• Rate of reproduction continues to decrease and death rate increases.
• Death rate exceeds rate of reproduction, so population begins to decline in size.

Question 17

What is a primary metabolite?

Answer 17

Substances produced by an organism that are essential to its growth; including amino acids, proteins, enzymes nucleic acids, ethanol… The production of primary metabolites matches population size.

Question 18

What is a secondary metabolite?

Answer 18

Substances produced by an organism that are not essential for growth, but increase its chance of survival. These include antibiotics. There is usually a significant time-lag between population growth and production of the metabolites.

Question 19

What are the factors that need to be controlled during fermentation?

Answer 19

• Temperature.
• Availability of nutrients.
• Oxygen concentration.
• pH.

Question 20

Why is temperature important in fermentation?

Answer 20

• If temperatures are too low, enzymes don’t work efficiently so rate of population growth and metabolite production is slow.
• If temperatures are too high, enzymes get denatured and the microorganisms get killed.
• Temperature probes and a water jacket maintains optimum temperature in an industrial fermenter to maximise yield.

Question 21

Why is nutrient availability important in fermentation?

Answer 21

• Constant availability of nutrients is essential for the microorganisms to keep growing, reproducing and producing desired metabolite.
• Paddles in industrial fermenters constantly stir fermentation medium to ensure organisms are always in contact with fresh medium and has access to nutrients.
• Nutrients are added at regular intervals during continuous fermentation.

Question 22

Why is oxygen concentration important during fermentation?

Answer 22

• Industrial processes that require the microorganisms to grow and respire aerobically need to maintain high oxygen concentration by constantly pumping in sterile air and low CO2 concentrations by allowing it to escape.
• This ensures that the microorganisms grow efficiently and don’t produce any unwanted products of anaerobic respiration.
• Industrial processes that require the the microorganisms to respire anaerobically need to ensure that there’s a minimum amount of oxygen present in fermenter, but also allow CO2 to escape, preventing build-up of pressure.

Question 23

Why is pH important in fermentation?

Answer 23

• Enzymes have a narrow pH over which they work.
• If pH in fermenter deviates from optimum, enzymes become less efficient.
• Growth and metabolite production becomes less efficient, reducing yield.
• If pH in fermenter deviates too much from optimum, enzymes become denatured and microorganisms die.
• pH probes and buffers are used to maintain constant pH in fermenter.

Question 24

What is the difference between a batch culture and a continuous culture?

Answer 24

• A batch culture is where starter population of microorganisms is mixed with set amount of nutrients in fermenter and left in closed culture. At the end, products are removed and the fermentation vessel emptied to repeat process.
• A continuous culture is when nutrients are added continuously/ at intervals to a population of microorganisms. The desired product is produced and removed continuously.

Question 25

What are the advantages of batch cultures?

Answer 25

• Easy to set up and maintain.
• Contamination only results in small batch being lost.
• Allows for the production of secondary metabolites.

Question 26

What are the advantages of continuous cultures?

Answer 26

• Higher growth rates as there’s never shortage of nutirents.
• More efficient due to continuous operation.
• Allows for the efficient production of primary metabolites.

Question 27

What are the disadvantages of batch cultures?

Answer 27

• Growth rate slows down as nutrients are slowly depleted.

- Less efficient than continuous process as there are time intervals between batches when fermenter not in operation.

Question 28

What is asepsis?

Answer 28

Absence of any unwanted microorganisms in the culture.

Question 29

What are the disadvantages of continuous cultures?

Answer 29

• More difficult to set up and maintain optimum growing environment in fermenter.
• If contamination occurs, large amounts of products are lost.

Question 30

Why is asepsis important in industry?

Answer 30

• Contaminant organisms compete with wanted microorganisms, reducing rate of growth and yield.
• Contaminant organisms may spoil product.
• Toxic chemicals may be produced by contaminant.
• May actively kill cultured microorganism.

Question 31

How can asepsis be achieved in a laboratory?

Answer 31

• Wearing protective clothing, e.g. Gloves…
• Sterilising all apparatus and surfaces coming into contact with microorganism beforehand.
• Working in fume cupboard where good air circulation removes airborne contaminants.
• Minimal contact between apparatus and bench surfaces reduces contamination.

Question 32

Why is asepsis important in the laboratory?

Answer 32

Contamination of a microorganism culture will result in inaccurate results being obtained.

Question 33

How is asepsis achieved in industry?

Answer 33

• Use of steam to disinfect fermenter between batches kills possible contaminants.
• Stainless steel work surfaces ensure no contaminants stick to surface.
• All nutrients are sterilised before adding into fermenter to prevent contamination.
• Air is filtered before pumping into fermenter to prevent airborne contamination.
• All open vents out of fermenter are lined with antiseptic solution.

Question 34

Why are enzymes used in industry?

Answer 34

• Enzymes are more specific, catalysing reactions to produce wanted products and fewer by-products than non-biological processes.
• Enzymes work at a much lower temperatures compared to those used for conventional chemical processes.

Question 35

What are the advantages of immobilised enzymes?

Answer 35

• Enzymes are not present in mixture with product, reducing purification/ downstream processing costs.
• Enzymes can be easily reused so don’t have to be replaced.
• More stable and are protected by immobilisation matrix, so are not as easily denatured by high temperatures/ pH.

Question 36

What are the disadvantages of immobilised enzymes?

Answer 36

• Setting up requires more time and materials, so is more expensive.
• Less active due to less exposure to to substrates (no free mixing).
• Contamination requires whole system to be stopped and replaced, which is more costly.

Question 37

What methods are there for immobilising enzymes?

Answer 37

1. Enzyme mixed with adsorption agent (glass beads, clay, resins…) and bind via intermolecular forces. Enzyme weakly bound and leakage is common
2. Enzymes are covalently cross-linked to each other using cross-linking agents (e.g. Gluteraldehyde) and then to insoluble supports (e.g. Clay). Enzymes are strongly bonded, reducing leakage, but only in small amounts.
3. Enzymes are trapped into gel beads or cellulose fibres in their unbound natural states. Rate of reaction reduced as substrates take time to move through entrapment complex and reach enzymes.
4. Enzymes are separated from substate mixture by semi-permeable membrane which allows substrates to diffuse in and products to diffuse out but is impermeable to enzyme, keeping it separate.