Expression of rice glutamate decarboxylase in Bifidobacterium longum enhances gamma-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.