Expression of rice glutamate decarboxylase in Bifidobacterium longum enhances γ-aminobutyric acid production

Bifidobacteria are important for the production of fermented dairy products and probiotic formulas but have a low capacity for gamma- aminobutyric acid (GABA) production. To develop a Bifidobacterium strain with an enhanced GABA production, we transformed Bifidobacterium longum with a rice glutamate decarboxylase (OsGADC) gene by electroporation. When the transformed strain was cultured in medium containing monosodium glutamate, the amount of GABA increased significantly compared with those of untransformed Bifidobacterium. Thus, by introducing a plant derived GAD gene, a Bifidobacterium strain has been genetically engineered to produce high levels of GABA from glutamate.