Glucose-based optimization of CHO-cell perfusion cultures

Area of Science:

• Biotechnology
• Bioprocess Engineering
• Cell Culture Technology

Background:

• Perfusion culture systems are vital for continuous biopharmaceutical production.
• Maintaining optimal glucose levels is critical for cell growth and product formation in CHO cell cultures.
• Acoustic filter cell retention offers an efficient method for cell immobilization in perfusion bioreactors.

Purpose of the Study:

• To develop and implement a robust glucose control strategy for perfusion cultures of Chinese hamster ovary (CHO) cells producing tissue plasminogen activator (t-PA).
• To investigate the impact of glucose usage on cell growth, consistency, and t-PA production.
• To establish optimal operating parameters for maximizing t-PA yield and sustainability.

Main Methods:

• Perfusion cultures of CHO cells using acoustic filter cell retention.
• Development of an off-line glucose analysis and predictive control protocol.
• Ramping glucose set point strategy during perfusion culture start-up.
• Monitoring glucose usage as an indicator of medium utilization and operational limits.

Main Results:

• A predictive glucose control protocol maintained set points within 0.5 mM without on-line sensors.
• Earlier perfusion onset with a ramping glucose set point improved culture start-up.
• t-PA concentration variability increased significantly beyond 22 mM glucose usage.
• Peak t-PA concentrations (>90 mg/L) were achieved at ~24 mM glucose usage but were unsustainable.
• Consistent t-PA concentration of 40 mg/L was achieved at 21.5 mM glucose usage.

Conclusions:

• A robust off-line glucose control strategy is effective for perfusion CHO cell cultures.
• Optimizing glucose usage is crucial for balancing t-PA yield and culture sustainability.
• The developed protocol enables precise control and provides insights into operational boundaries for bioprocess optimization.