Microbial acetate oxidation in horizontal rotating tubular bioreactor

Area of Science:

• Biotechnology
• Environmental Engineering
• Microbial Ecology

Background:

• Continuous bioprocesses are crucial for industrial applications.
• Horizontal rotating tubular bioreactors (HRTB) offer potential for enhanced mass transfer and microbial retention.
• Acetate oxidation by mixed microbial cultures is a relevant model for aerobic biotransformations.

Purpose of the Study:

• To evaluate the feasibility of using HRTB for continuous aerobic bioprocesses.
• To model aerobic acetate oxidation using a mixed microbial culture in an HRTB.
• To identify key operational parameters influencing bioprocess efficiency.

Main Methods:

• Aerobic oxidation of acetate in a horizontal rotating tubular bioreactor (HRTB).
• Utilized a mixed microbial culture, allowing growth in suspension and as a biofilm.
• Monitored bioprocess efficiency through acetate concentration and chemical oxygen demand (COD) measurements.

Main Results:

• Acetate inlet concentration and feeding rate significantly influenced oxidation efficiency.
• Bioreactor rotation speed had minimal impact on bioprocess dynamics.
• Acetate concentration and pH gradients were more pronounced at lower feeding rates.
• Volumetric load was the most critical parameter: high loads (>2 g/L/h) resulted in poor efficiency (17-50%), while lower loads (0.14-0.58 g/L/h) achieved complete acetate consumption.

Conclusions:

• HRTB is a suitable platform for continuous aerobic bioprocesses.
• Optimizing volumetric load is essential for efficient acetate oxidation in HRTB.
• The system supports microbial growth in both suspended and biofilm forms, enhancing process robustness.