L-Phenylalanine production

Wild strains of E. coli are not used for L-phenylalanine production by direct fermentation. 

We can summarise the enzymatic methods of L-phenylalanine production as follows ... 

The elimination of the amino donor, L-aspartic acid, resulted in an almost complete reduction of activity. Neither cell permeabilisation nor cofactor (pyridoxalphosphate) addition were essential for L-phenylalanine production. Maximum conversion yield occurred (100%, 22 g r) when the amino donor concentration was increased. Aspartic add was a superior amino donor to glutamic add 35 g l 1 was used. 

Production of L-phenylalanine proved to be an attractive target for new startup biotechnology companies as well as established companies. However, this opportunity disappeared once the aspartame manufacturers own L-phenylalanine production plant came on stream. 

Gerigk, M.R., Maass, D., Kreutzer, A., Sprenger, G., Bongaerts, J., Wubbolts, M. and Takors, R. (2002) Enhanced pilot-scale fed-batch L-phenylalanine production with recombinant escherichia coli by fully integrated reactive extraction. Bioprocess and Biosystems Engineering, 25, 43. 

Takors, R. (2004) Model-based analysis and optimization of an ISPR approach using reactive extraction for pilot-scale L-phenylalanine production. Biotechnology... 

In contrast to the various fermentation and bioconversion approaches that have used enzyme stereoselectivity to syntlresize L-phenylalanine as a single isomer, additional methods have been developed that rely on the same stereoselectivity to resolve racemic mixtures of chemically synthesized amino acids. One such general approach, which has been successfully commercialized for L-phenylalanine production, relies on cleavage of the L-isomer of a D,L-a-amino acid amide mixture by an enantiospecific amidase enzyme. The general procedure operated... 

Fig. 15 L-Phenylalanine production using an L-phenylalanine ammonia lyase.

As much as 600000 cycles have been reported for the FDH/formate-driven PEG-NADH-recycling system in the case of L-phenylalanine production (Fig. 2) by reductive amination with phenylalanine dehydrogenase [99]. 

Gerigk, M. et al (2002) Process control for enhanced L-phenylalanine production using different recombinant Escherichia coli strains. Biotechnol. Bioeng., 80, 746-754. 

Loss control credit factors, process hazard analysis, 873-874 Love Canal incident, 891 Low-alloy steels, equipment cost, 205 Lower explosive limit (LEL), 863 Lower flammability limit (LFL), 863 L-phenylalanine production bacteria, filtering, 1014 continuous crystallizers, 1014 continuous filtration, 1014 filtering, 1014 intermediate storage, 1014 ion exchange column, 1014... 

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