A direct comparison of approaches for increasing carbon flow to aromatic biosynthesis inEscherichia coli

• DOI: 10.1007/bf01570148
• Publication Date: 2005-04-27T18:08:48Z
• Authors: G Gosset; J Yong-Xiao; A Berry
• Keywords: Strain (injury); PEP group translocation; Carbon fibers

Different approaches to increasing carbon commitment to aromatic amino acid biosynthesis were compared in isogenic strains of Escherichia coli. In a strain having a wild-type PEP:glucose phosphotransferase (PTS) system, inactivation of the genes encoding pyruvate kinase (pykA and pykF) resulted in a 3.4 fold increase in carbon flow to aromatic biosynthesis. In a strain already having increased carbon flow to aromatics by virtue of overexpression of the tktA gene (encoding transketolase), the pykA and/or pykf mutations had no effect. A PTS- glucose+ mutant showed a 1.6-fold increase in carbon flow to aromatics compared to the PTS+ control strain. In the PTS- glucose+ host background, overexpression of tktA caused a further 3.7-fold increase in carbon flow, while inactivation of pykA and pykF caused a 5.8-fold increase. When all of the variables tested (PTS-glucose+, pykA, pykF, and overexpressed tktA) were combined in a single strain, a 19.9-fold increase in carbon commitment to aromatic biosynthesis was achieved.