title: Effects of glutamate decarboxylase and gamma-aminobutyric acid (GABA) transporter on the bioconversion of GABA in engineered Escherichia coli.
abstract: Gamma-aminobutyric acid (GABA) is a non-essential amino acid and a precursor of pyrrolidone, a monomer of nylon 4. GABA can be biosynthesized through the decarboxylation of L: -glutamate by glutamate decarboxylase. In this study, the effects of glutamate decarboxylase (gadA, gadB), glutamate/GABA antiporter (gadC) and GABA aminotransferase (gabT) on GABA production were investigated in Escherichia coli. Glutamate decarboxylase was overexpressed alone or with the glutamate/GABA antiporter to enhance GABA synthesis. GABA aminotransferase, which redirects GABA into the TCA cycle, was knock-out mutated. When gadB and gadC were co-overexpressed in the gabT mutant strain, a final GABA concentration of 5.46 g/l was obtained from 10 g/l of monosodium glutamate (MSG), which corresponded to a GABA yield of 89.5%.
authors.affiliation: School of Chemical Engineering and Bioengineering, University of Ulsan, Nam-gu, Ulsan, Korea.
authors.forename: Tam Dinh
authors.initials: TD
authors.lastname: Le Vo
authors.forename: Tae Wan
authors.initials: TW
authors.lastname: Kim
authors.forename: Soon Ho
authors.initials: SH
authors.lastname: Hong
mesh_terms: D004926:Escherichia coli / Q000502:physiology*; D050485:GABA Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D024861:Genetic Enhancement / Q000379:methods*; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods*; D015854:Up-Regulation / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis*
chemical_list: D050485:GABA Plasma Membrane Transport Proteins; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase