Week 3 Flashcards
What is traditional bioprocessing?
It uses cell culture to produce a product, treating the cell as a factory (e.g. antibiotics, vaccines, antibodies, recombinant proteins).
In stem cell bioprocessing, what is the product?
The cells themselves.
Give two applications of stem cell bioprocessing.
Drug screening programmes and stem cell therapies.
How does cell type affect growth and functional product production in bioreactors?
Growth ease decreases from bacteria to human cells; product functionality increases.
Which cells have the shortest doubling time?
Bacteria (30 min to 1 hour).
What are key characteristics of mammalian cells for bioprocessing?
Size: 10-50 μm, extremely shear sensitive, secreted proteins, doubling time: 24-48h.
What scale is used for monoclonal antibody production?
> 10,000 Litres.
What scale is used for viral vaccine production?
2,000 Litres.
What scale is used for mesenchymal stem cells for therapy?
50 Litres.
What is seed train in scale-up production?
A stepwise increase in culture volume to reach large production scales (e.g., from 5 mL to 10,000 L).
What is the main difference between scale-up and scale-out?
Scale-up increases volume in a single unit; scale-out uses multiple smaller units in parallel
What is a key risk in scale-up production?
High contamination risk leading to maximal loss.
What is a key drawback of scale-out production?
Labor intensive unless automated and less cost-effective.
Why is scale-up not just “making the pot bigger”?
It requires careful engineering considerations (e.g. gradients, mixing) to avoid process failure.
Name two issues with inefficient scale-up.
Lower product yield and mechanical/genetic instability.
Examples of planar culture vessels?
T-flasks, multilayer plates, cell factories, roller bottles.
Main disadvantage of planar vessels?
Low surface area-to-volume ratio; unsuitable for large-scale production.
What’s the difference between a bioreactor and a fermenter?
Bioreactor: general bio-based process; Fermenter: for growing cells (e.g., bacteria).
Name 3 types of submerged bioreactors.
Mechanical (stirred tank), Hydraulic (fixed/fluidised bed), Pneumatic (airlift).
Key advantage of pneumatic bioreactors?
Low shear, no moving parts → less contamination.
Main challenge of pneumatic bioreactors?
Foaming.
What’s packed bed used for?
Immobilised cells for long-term, high-density cultures.
Main disadvantage of fixed bed?
Non-homogeneous distribution, difficult cell harvest.
What kind of cells can be grown in hollow fibre systems?
Anchorage-dependent or independent.
