Integrated L-phenylalanine separation in an E. coli fed-batch process: from laboratory to pilot scale

Area of Science:

• Biochemical Engineering
• Separation Technology
• Microbial Fermentation

Background:

• Microbial production of L-phenylalanine (L-Phe) can be inhibited by by-product accumulation.
• Efficient separation is crucial for maximizing L-Phe yield and purity in fed-batch fermentations.

Purpose of the Study:

• To investigate pilot-scale reactive extraction for integrated L-Phe separation.
• To prevent inhibition of microbial L-Phe production by by-product accumulation.

Main Methods:

• Developed an optimal reactive-extraction system using a kerosene phase with di-2-ethylhexyl phosphonic acid (DEHPA) and a sulfuric acid stripping phase.
• Employed two membrane contactors to achieve efficient mass transfer.
• Used simple modeling to derive mass-transfer coefficients.

Main Results:

• Achieved concentration factors greater than 4 in the stripping phase.
• Reactive extraction resulted in 98% cation portion of L-Phe in the stripping phase.
• Attained final product purity exceeding 99% after L-Phe precipitation.
• Observed a doubling of L-Phe/glucose yield when simulating integrated separation.

Conclusions:

• The developed reactive-extraction system is highly efficient for L-Phe separation.
• Integrated separation significantly enhances L-Phe production yield and purity.
• This technology offers a promising solution for industrial L-Phe production.