Extractive fermentation for enhanced propionic acid production from lactose by Propionibacterium acidipropionici

Area of Science:

• Biotechnology
• Chemical Engineering
• Metabolic Engineering

Background:

• Propionic acid is a valuable chemical produced via fermentation.
• Conventional fermentation processes suffer from low product concentration and yield due to product inhibition.
• Efficient recovery methods are needed to overcome these limitations.

Purpose of the Study:

• To develop and evaluate an extractive fermentation process for enhanced propionic acid production from lactose.
• To investigate the impact of in-situ product removal on fermentation performance.
• To analyze the effects of key process parameters on the extractive fermentation.

Main Methods:

• Utilized an amine extractant and a hollow-fiber membrane extractor for in-situ propionic acid removal.
• Conducted comparative studies between extractive and conventional batch fermentation.
• Optimized parameters including propionic acid concentration, pH, and amine content.

Main Results:

• Extractive fermentation achieved a 5-fold increase in productivity (1 g/(L.h)) and over 20% higher yield (0.66 g/g).
• Final propionic acid concentration reached 75 g/L with approximately 90% purity.
• Acetate and succinate production were significantly reduced, indicating a potential metabolic shift.

Conclusions:

• Extractive fermentation with amine and hollow-fiber membranes is a highly effective strategy for propionic acid production.
• Reduced product inhibition and altered metabolic pathways contribute to improved fermentation outcomes.
• The process demonstrated stability and consistent performance over a 1.5-month period.