Applied Microbiology Flashcards
What organism makes penicillin ?
penicillium chrysogenum
What is white biotechnology?
industrial processes to produce chemicals, materials and energy in a sustainable and eco-friendly manner
What are some market pulls and technology pushes on white biotechnology ?
- Market pulls: desire for chemical feedstocks to be manufactured from renewable sources
- Technology push: improved techniques for genetic modification, known as synthetic biology (engineering biology)
What is synthetic biology ?
The design and engineering of biologically based parts, novel devices and systems as well as the redesign of existing, natural biological systems.
What is the sugar economy ?
- Aim to move an economy based on renewable biomass sugars as a source of fuels and chemicals rather than fossil carbon
- It is essential to avoid competing with the human food supply, the basis must be non-food photosynthetic carbon
What can microorganisms do ?
- Consume organic compounds (bioremediation)
- Produce fermentation end products (ethanol, butanol, acetic acid, lactic acid)
- Produce metabolic intermediates (citric acid, amino acids)
- Produce second metabolites (antibiotics): usually strains mutated or engineered for high production
- Produce proteins (enzymes, recombinant therapeutic proteins)
- Produce biomass (single cell protein, eg Quorn)
How do we grow microorganisms on a large scale ?
- Surface fermentations: good aeration, hard to automate, prone to contamination
- Submerged fermentations: bioreactors
- For aerobic organisms, oxygen supply is the main challenge
What are the components of an aerated stirred tanks ?
- Cylindroconical steel vessels
- Converged bottom, no dead spots
- Domed top contains pressure
- Sterile air via sparger
- Impeller breaks up bubbles for good oxygen transfer
- Cooling cools remove waste heat
- Baffles prevent vortex formation
What is an airlift reactor ?
- Mixing purely by circulation of fluid driven by bubbles – no impellers
- Low shear, low energy use
What are the primary and secondary growth ?
- Primary products: produced during exponential growth
- Secondary products: produced as growth slows, and in stationary phase
What is batch fermentation ?
all components present at the start. Simplest; inefficient use of reactor time
What is fed batch ?
feed with concentrated nutrients to prolong production phase. More efficient use of the reactor time; essential when high nutrients levels prevent product formation
What is continuous fermentation ?
add fresh medium and remove spent medium at constant rate. Most efficient. Not sustainable for highly mutated strains which may revert
How does the graph of the 3 types of fermentation compare ?
batch: substrate decreases to zero
fed batch: substrate decreases then plateau at 50%, product increases exponentially
Continuous: product and substrate plateau, with more product than substrate
