This document discusses scaling up animal cell and microbial production processes from small to large scale. Key points include: 1. Maintaining optimal physiological conditions as processes are scaled up from small to large bioreactors. 2. Factors that must be considered when scaling up include the fermentor/bioreactor system, agitation, pH, temperature, and dissolved oxygen levels. 3. Scaling up usually occurs gradually in 10x increments from 1L to 10,000L bioreactors. Limiting factors include oxygen supply, shear damage from mixing, and toxic metabolite build up.

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