TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In (M1), (I) is from a strain of the Enterobacteriaceae family, preferably E.coli or Pantoea. (I) or E.coli host cell is PTS-/Glu+. (M1) further involves inactivating the expression of an endogenous gene encoding a polypeptide having RpoS, Edd, Pta, AckA or MgsA activity, and transforming (I) with a DNA fragment comprising an exogenous promoter, where the DNA fragment including the exogenous promoter is integrated into the host cell chromosome to replace the endogenous promoter, which is operably linked to a PEP carboxylase coding sequence. PEP carboxylase is overexpressed. (M1) further involves isolating the desired product from the culture media. Enhancement of the production of an aromatic amino acid in an E.coli host cell, involves modifying E.coli host cell by inactivating an endogenous arcA gene, culturing the modified host cell as in (M1) to allow production of an aromatic amino acid, and isolating the aromatic amino acid from the culture media. (M2) further involves inactivating an endogenous rpoS gene, and inactivating an endogenous gene encoding a polypeptide having phosphogluconate dehydratase activity, phosphotransacetylase activity, acetyl kinase activity or methylglyoxyal synthase activity. (M2) further involves isolating the modified (I). The endogenous arcA gene is inactivated by a deletion. The endogenous gene encoding a polypeptide having phosphogluconate dehydratase activity is an edd or pta gene. The endogenous gene encoding a polypeptide having acetyl kinase activity is an ackA gene. The endogenous gene encoding a polypeptide having methylglyoxyal synthase activity is mgsA gene. (I) is preferably E.coli or Pantoea.Preferred Bacterial Strain: (I) and (II) are chosen from Escherichia, Pantoea, Klebsiella, Gluconobacter and Erwinia, preferably a strain of E.coli. The endogenous arcA gene is deleted. (II) further comprises an inactivated endogenous mgsA, edd and rpoS. The overexpressed polypeptide having PEP carboxylase is operably linked to an exogenous promoter, which is a GI promoter. (III) further comprises an overexpressed polypeptide having PEP carboxylase activity. In (III), the endogenous rpoS gene is deleted. (II) has a PTS-/Glu+ phenotype, which is derived from a bacterial strain originally capable of utilizing a PTS for carbohydrate transport. (II) is E.coli EXAMPLE - Strains of Escherichia coli MG1655 and strain KLNDH having inactivated ndh gene were taken, and the arcA gene was deleted using the plasmid that codes for 3 protein activities, and increase the frequency of homologous recombination, where the activities promoted the homologous recombination between the chromosome of E.coli and a DNA mutagenic cassette. A PCR reaction was used to generate the mutagenic cassette that contained the regions of homology with the chromosome at both ends. The arcA mutagenic cassette was obtained by PCR using plasmid pKD3 and the primers ArcA1 and ArcA2 having the sequences 5'-cacattcttatcgttgaagacgagttggtaacacgcaacacgtgtaggctggagctgcttc-3' and 5'-ttccagatcaccgcagaagcgataaccttcaccgtgaatggtcatatgaatatcctccttag-3' that contained the regions of homology to the arcA gene and to a FRT-cat cassette present in pKD3. The proper integration of the arcA mutagenic cassette to chromosome of E.coli was confirmed by sequencing the chromosomal region using primers ArcA3 and ArcA4. The 250 ml flask containing 10 ml of minimal media TM2 containing potassium phosphate (13.6 g/l), citric acid monohydrate (2 g/l), ferric ammonium citrate (0.3 g/l), ammonium sulfate (3.2 g/l), yeast extract (5 g/l) and solution of trace elements (1 ml), was inoculated with an overnight culture of the strain MG1655 and MG1655 having deleted arcA gene. Cultures were incubated at 37 degreesC in a orbital shaker Psyco Therm. Samples were taken at different time intervals and the optical density at 600 nm was measured. Cells were removed by centrifugation and the supernatants were utilized to quantify glucose and acetate. The results showed that the MG1655 strain with the arcA deletion grew to a higher cell density and produced less acetate. KLNDH arcA deleted strain and KLNDH strain were transformed with pSYCO101, which carries the genes to convert dihydroacetone-phosphate into glycerol, to obtain the KLNDH 101 arcA deleted strain and KLNDH 101 strain. The result showed that the KLNDH arcA deleted strain produced more glycerol (22.5 g/l) and was more efficient for the conversion of glucose into product than the wild type strain.