Background

A client approached us with a recombinant protein expressed in E. coli, developed only at 5 L lab scale. The process suffered from low yield, long fermentation times, and batch inconsistency. The objective was to scale up to 100 L while improving productivity and reproducibility.

Key Challenges

• Acetate accumulation due to overflow metabolism
• Suboptimal induction conditions
• Oxygen limitation during scale-up
• Inclusion body formation reducing soluble yield

Our Approach

• Media & Feeding Optimization: Implemented carbon-limited fed-batch with exponential feeding, reducing acetate from ~3.5 g/L to <0.5 g/L.
• Process Parameter Control: Adjusted temperature, pH, and dissolved oxygen to improve protein folding and reduce stress.
• Induction Strategy: Delayed induction at high cell density with reduced IPTG, increasing soluble protein fraction.
• Scale-Up Control: Maintained oxygen transfer and feeding consistency across 5 L → 10 L → 100 L using scale-down simulations and DO-stat feeding.

Results

Impact