Fully integrated L-phenylalanine separation and concentration using reactive-extraction with liquid-liquid...

Area of Science:

• Biotechnology
• Biochemical Engineering
• Metabolic Engineering

Background:

• Industrial production of L-phenylalanine (L-phe) often faces challenges with product inhibition and low yields.
• Efficient separation techniques are crucial for optimizing fed-batch fermentation processes.

Purpose of the Study:

• To develop and evaluate a novel in situ product recovery (ISPR) system for integrated L-phe separation.
• To improve the overall efficiency and yield of L-phe production using a recombinant E. coli strain.

Main Methods:

• A recombinant L-tyrosine auxotrophic E. coli strain (F-4/pF81) was engineered for L-phe production.
• A reactive extraction system using kerosene, D(2)EHPA, and sulfuric acid in liquid-liquid centrifuges was employed for ISPR.
• The ISPR system was integrated with a 20 L fed-batch bioreactor with controlled glucose and tyrosine levels.

Main Results:

• The ISPR approach enabled an extended product formation period at a rate of 0.25 mmol/(g*h).
• Reduced by-product formation and a 28% relative increase in glucose/L-phe yield were observed.
• Extraction rates were approximately three times higher than those of a published membrane-based process.

Conclusions:

• The novel ISPR approach is superior to non-ISPR processes for L-phe production.
• This integrated separation strategy significantly enhances the economic viability of L-phe fermentation.