Acetone-butanol-ethanol fermentation in a continuous and closed-circulating fermentation system with PDMS membrane...

Area of Science:

• Biotechnology
• Chemical Engineering
• Microbiology

Background:

• Acetone-butanol-ethanol (ABE) fermentation is a key biofuel production process.
• Achieving efficient and stable long-term fermentation remains a challenge.
• Membrane bioreactor technology offers potential for process intensification.

Purpose of the Study:

• To develop and evaluate a long continuous and closed-circulating fermentation (CCCF) system for ABE production.
• To compare the performance of continuous versus intermittent coupling modes in a PDMS membrane bioreactor.
• To assess the adaptability of Clostridium acetobutylicum in a long-term CCCF system.

Main Methods:

• Utilized a polydimethylsiloxane (PDMS) membrane bioreactor with Clostridium acetobutylicum.
• Implemented two experimental cycles: intermittent coupling with pervaporation and continuous coupling.
• Monitored fermentation parameters including cell weight, glucose consumption, butanol productivity, and butanol production over extended periods (274 h and 300 h).

Main Results:

• The continuous coupling mode significantly outperformed the intermittent coupling mode.
• Continuous coupling achieved higher average cell weight (1.68 g L⁻¹), glucose consumption rate (1.12 g L⁻¹h⁻¹), butanol productivity (0.205 g L⁻¹h⁻¹), and butanol production (61.43 g L⁻¹).
• Microbial adaptation to the long-term CCCF membrane bioreactor system was confirmed by observed peak values in time-course profiles.

Conclusions:

• Continuous coupling in a PDMS membrane bioreactor is a superior strategy for enhancing ABE fermentation efficiency.
• The developed CCCF system demonstrates robustness and microbial adaptability for sustained biofuel production.
• This approach holds promise for industrial-scale acetone-butanol-ethanol fermentation.