Metabolic engineering of Escherichia coli for the production of phenylalanine and related compounds

In this review, the metabolic engineering approaches including those used by the authors in creating phenylalanine producers based on Escherichia coli were systematized. Optimization of the amino acid biosynthesis was conducted in order to obtain significant quantities of phenylalanine and to ensure the availability of its direct precursors in cell metabolism—erythrose 4-phosphate and phosphoenolpyruvic acid. The possibility of altering global regulation mechanisms was investigated for a full reorientation of the metabolism to phenylalanine synthesis with the use of Csr (carbon storage regulator). The identification of the aromatic amino acids exporter YddG is associated with the use of the phenylalanine producer as a test-system. Novel approaches to phenylalanine producer construction (use of the “leaky” allele tyrA—ssrA, promoters of the phosphate regulon), as well as new methods of obtaining producers of similar amino acid tyrosine, were discussed. Examples of the synthesis of useful aromatic compounds from phenylalanine or its precursor, phenylpyruvic acid, with E. coli as the ecipient for foreign gene expression were examined.