Industrial Microbiology Dr. Butler 2011

1. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
Scaling up animal cell/microbial processes
• optimal physiological conditions obtained via small
scale processes maintained for large scale operation
• must consider:
1. fermentor/bioreactor system
2. control of agitation, pH, temperature, dissolved
oxygen

2. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
T-flasks

3. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
Spinner bottle

4. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
Multiple process vs. unit process
• can have 1000 100 mL flasks or a single 100 litre
fermentor (same volume)
1. Multiple process
• easy to replicate samples and conditions, large surface
area/volume ratio, tedious to take care of all samples,
labor intensive
2. Unit process
• good for large scale production of biological products,
ease of handling, decreased possibility of
contamination

5. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
Butler, M. 2004. Animal cell culture and technology 2nd ed. London and New York:Garland Science/BIOS Scientific Publishers. P203.

6. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
Suspension vs. Anchorage-dependence
• suspension cells are readily scaled up to production
level using similar fermentation vessels as microbial
cells (with modifications)
• anchorage-dependent cells require a surface for
attachment in order to grow
→ grow as static cultures (i.e. hollow fibres)
→ grow on microcarriers, in a stirred tank reactor
(fermentor)

7. Cell culture processes
• Anchorage-dependent systems
Microcarrier (dextran, collagen
or plastic) : 200 µm
Advantages:
-Higher cell yields
- increased productivity.
- ↑ surface ratio (100 -200 cells).
- suspension cultures
• Suspension systems: > Industrial culture

8. Cytopore microcarriers

9. Cell Culture system
• Vero cells
•Why? Regulated by WHO
• already licensed for vaccine
production such as polio, influenza,
rabies, others
• Serum-free medium
•Why? Safety and reproducibility
• Microcarriers
•Why? Scalability and ease of infection

10. Macroporous microcarrier

11. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
Usually scale up 10x at a time:
1 → 10 → 100 → 1000 → 10,000 L
Factors limiting scale-up
• supply of oxygen
• shear damage from mixing
• build up of toxic metabolites

12. Lecture 9 Animal Cell Biotechnology
Scaling up the production process
during scale up decreased product yields may be
experienced due to the following:
1. inoculation – must consider quality and quantity of
inoculum used to start process
$
2. choice of medium – cheaper materials often used for large
$
$
scale production due to cost limitations - omission /
reduction of serum, antibiotics
3. large scale sterilization – longer sterilization times may
result in degradation of heat labile compounds, reducing
quality of media
4. development of gradients - larger fermentors/bioreactors
may be subject to development of nutrient, temperature,
pH, and oxygen gradients
5. other factors -scaling up may also alter the generation of
foam, shear forces

13. Lecture 9 Animal Cell Biotechnology
Scaling up the production process:
The Stirred Tank Reactor
• bioreactor is another term for fermentor
• stirred tank reactor simplest and most widely used
system (pot and paddle)
→ small vessels (<20 litres) made of glass
→ large vessels (>20 litres) made of stainless steel

14. Bioreactor (Fermenter)
• Vessel that allows the growth of cells.
• Stirred tank bioreactor (STR).
Growth: Bacteria, yeast, mammalian cells.
• Homogeneous solution mixed by an impeller:
-Laminar stirred: Just one dimension to lift the
liquid.
Cultures >1L: Uneven
oxygen exchange and
poor nutrient distribution
www.corning.com

15. Stirred Tank Reactor
• Shape:
-curve bottom mammalian cells
-square bottom poor mixing
• Materials used:
Vessel up to 10 L (glass)
Head plate steel stainless
• Heat control: (heat pad or jacket water)
- Constant To
-mammalian cell culture (37o C)

16. Lecture 9 Animal Cell Biotechnology
Scaling up the production process:
The Stirred Tank Reactor
Butler, M. 2004. Animal cell culture and technology 2nd ed. London and New York:Garland Science/BIOS Scientific Publishers. P156.

17. Fig. 9.2

18. Fig. 9.3