Isolation and identification of lactic acid bacteria. (A) Thin-layer chromatogram of different bacterial strains. Strain SS6 produced the greatest amount of GABA (arrows). (B) The levels of GABA produced by bacterial strains. (C) Morphology of strain SS6 in MRS culture and isolated culture. *P<0.05, SS6 group vs. LB2, LB6, SC5, SC6 or SC9 group. GABA, γ-aminobutyric acid; MRS, de Man, Rogosa and Sharpe agar.