A novel bioreactor-cell precipitator combination for high-cell density, high-flow fermentations.

Area of Science:

• Biotechnology
• Biochemical Engineering
• Microbial Fermentation

Background:

• Traditional chemostats face limitations in maintaining high cell densities during continuous fermentation.
• Cell recycle is crucial for enhancing productivity but often requires complex external systems.
• Simultaneous fermentation and cell recycle in a single unit offers potential for process intensification.

Purpose of the Study:

• To investigate a novel bioreactor design integrating fermentation and cell recycle.
• To evaluate the bioreactor's performance in achieving high cell densities and productivities.
• To explore the potential applications and advantages of this integrated system.

Main Methods:

• A novel bioreactor with an inclined side-arm for enhanced cell sedimentation and recycle was designed.
• Continuous flow fermentation experiments were conducted using Saccharomyces cerevisiae.
• The bioreactor's performance was assessed based on cell density, broth withdrawal rates, and ethanol productivity.

Main Results:

• The bioreactor successfully achieved simultaneous fermentation and cell recycle.
• Significantly increased steady-state cell densities were obtained, preventing washout at high flowrates.
• High ethanol productivities were demonstrated, with potential for further enhancement through scale-up.

Conclusions:

• The novel bioreactor design effectively integrates fermentation and cell recycle, leading to substantial improvements in cell density and productivity.
• This system offers advantages over conventional chemostats, including enhanced resistance to contamination and potential benefits for recombinant microorganisms and mixed cultures.
• The design shows promise for various fermentation applications, including those involving stationary cultures under continuous flow.