6.4..6: Other processes involving biochemistry Flashcards
Which conditions in a fermenter need to be controlled?
- Conc. of product (build up affects synthesis process)
- pH (affects enzyme activity)
- Temp (too high→denature, too low→ limited growth)
- Oxygen (most microorganisms respire aerobically)
- Nutrients to grow and synthesise products (carbon, nitrogen, minerals, vitamins)
What are primary metabolites?
- Synthesised during normal metabolism.
- When microorganisms are actively growing.
What are secondary metabolites?
- Produced when cells are put under stress.
- e.g. high population density or limited nutrients.
- during stationary growth phase.
Describe continuous culture.
- Broth topped up with nutrients.
- Nutrients used by microorganisms.
- Some broth removed regularly to extract product and remove cells.
- Microorganisms kept growing at a specific rate.
Why are some cells removed in continuous culture?
-To prevent overcrowding.
Describe batch culture
- Culture set up with limited nutrient availability.
- Allowed to ferment for a specific time.
- Fermenter emptied and the product is extracted from the culture.
How is penicillin produced?
- Through fermentation by the fungus penicillium.
- It is a secondary metabolite and is produced once the population has reached a certain size.
- Batch culture.
What are the three steps in producing antibiotics?
- Fermenter run for 6-8 days, the culture is then filtered to remove cells.
- Antibiotic precipitated as crystals by the addition of potassium compounds.
- Antibiotics mixed with inert substances and prepared for administration.
How is insulin produced?
- Gene for human insulin combined with plasmid (vector)
- Gene inserted into E.coli
- GM bacteria produces vast amounts of human insulin at a low cost.
- Continuous culture.
What is asepsis?
-Ensuring that sterile conditions are maintained.
The nutrient medium would also support the growth of unwanted microorganisms which would reduce production because…
The microorganisms:
- Compete with cultured microorganisms (nutrients, space)
- Reduce yield of product.
- Spoil product.
- Produce toxic chemicals.
- Destroy cultured microorganisms.
What is bioremediation?
-The use of microorganisms to clean soil and underground polluted sites.
(toxic substances converted to less harmful substances by microorganisms)
Give examples of bioremediation.
- Bacterium used to break down crude oil in oil spills.
- Solvents and pesticides can be treated.
What does bioremediation involve?
- stimulate growth of suitable microbe.
2. Microbe uses contaminants as food source.
What are the advantages of bioremediation?
- Uses natural systems.
- Less labour/equipt. needed.
- In-situ treatment.
- fewer waste products.
- reduced risk of exposure to clean up personnel.
