Dialysis continuous process for ammonium-lactate fermentation of whey: experimental tests

Area of Science:

• Biotechnology
• Biochemical Engineering
• Fermentation Technology

Background:

• Lactose fermentation is crucial for producing valuable compounds like ammonium lactate.
• Traditional batch and continuous fermentation methods face limitations with concentrated substrates and product purity.
• Dialysis continuous fermentation offers a potential solution to overcome these challenges.

Purpose of the Study:

• To validate theoretical predictions for a dialysis continuous fermentation process.
• To assess the efficiency and productivity of fermenting whey lactose to ammonium lactate.
• To compare the dialysis continuous process with traditional fermentation methods.

Main Methods:

• Laboratory experiments using a 5-liter fermentor with Lactobacillus bulgaricus.
• Non-aseptic continuous operation for 94 days with pH and temperature control.
• Dialysis against water to remove ammonium lactate and maintain constant pH.

Main Results:

• The process remained homofermentative with increasing conversion efficiency over time.
• High substrate conversion (97%) was achieved with a 19-hour retention time.
• Membrane fouling required cleaning every 4 weeks, but the process demonstrated high efficiency and productivity.

Conclusions:

• Dialysis continuous fermentation enables the use of more concentrated substrates for lactose fermentation.
• This method is more efficient in substrate conversion rates compared to non-dialysis processes.
• The process yields a purer ammonium lactate effluent, offering advantages for downstream applications.