An immobilized cell reactor with simultaneous product separation. II. Experimental reactor performance

Area of Science:

• Biochemical Engineering
• Separation Processes
• Bioreactor Design

Background:

• Product inhibition significantly limits productivity in many fermentation processes.
• Simultaneous product separation can overcome inhibition and increase bioreactor efficiency.
• Existing reactor designs struggle to balance reaction and separation effectively.

Purpose of the Study:

• To investigate the application of the Immobilized Cell Reactor-Separator (ICRS) for ethanol production from whey lactose.
• To evaluate the performance of the ICRS in terms of reaction rates and product separation efficiency.
• To optimize reactor operation for high productivity and efficient separation.

Main Methods:

• Development and application of a two-column ICRS: a cocurrent 'enricher' and a countercurrent 'stripper'.
• Utilized a four-phase tubular reactor system with immobilized cells on an absorbent matrix.
• Investigated operation in both liquid and gas continuous flow regimes.

Main Results:

• The ICRS achieved high cell density loading (up to 92 g/L reactor) in the enricher.
• Ethanol productivity ranged from 50-160 g/L h in the enricher and 0-32 g/L h in the stripper.
• A separation efficiency of up to 98% was achieved, demonstrating effective product recovery.

Conclusions:

• The ICRS, particularly with cells immobilized on an absorbent matrix, enables efficient operation in the gas continuous regime.
• This system significantly enhances bioreactor productivity by enabling simultaneous reaction and separation of volatile products.
• The ICRS shows great promise for improving the economics of fermentation processes, such as ethanol production from lactose.