1. Large-Scale Production of Recombinant Proteins Lecture 6
ISAT 451, Fall 2003
College of Integrated Science and Technology
James Madison University

2. Large-Scale Protein Production
Most commercially valuable proteins (industrial enzymes or therapeutic proteins) require living cells to make the product
Although cells can be readily grown in a standard 200 ml laboratory flask, commercial production may require containers in excess of 10,000 liters
What are the limitations of large-scale production?

3. Microbial Growth Conditions
Sterile culture medium containing a carbon source and essential salts or an enriched medium
Pure culture for inoculation
oxygenation and mixing
Regulation of temperature
Regulation of pH

4. Microbial Cell Growth

5. Batch Fermentation
Sterile medium is inoculated and fermentation proceeds without the addition of fresh growth medium.

6. Fed Batch
Nutrients are added at intervals during fermentation. No growth medium is removed.

7. Continuous Fermentation
Fresh growth medium is added continuously during fermentation and spent medium is removed.
Fermentation can last up to 1,000 hours.

8. Why do Cells Stop Growing?
Depletion of nutrients
Lack of oxygen
Change in pH
Growth inhibition from metabolic end products

9. Stirred Tank Bioreactors
An external motor is used to agitate the growth medium with impellers.
Sterile air or combinations of gases can be introduced (sparging)

10. Bubble Column Bioreactor
Introduction of sterile air or pure gases is used for agitation and oxygenation.

11. Internal-Loop Airlift Bioreactor
Sterile air or pure gases are introduced to create circulation internal to the reactor.

12. External-Loop Airlift Bioreactor
Sterile air or pure gases are introduced to drive circulation through an external loop.