Abstract: γ-Aminobutyric acid (GABA) production of lactic acid bacteria in chickpea milk was enhanced by compound mutagenesis, aiming to lay a basis for the development of functional foods rich in GABA. Ultraviolet (UV) irradiation and combined UV-LiCl were used for the mutagenesis of Lactobacillus plantarum M-6. The optimal UV irritation time was 240 s, and the optimal LiCl concentration was 1.25%. A total of 21 mutants with higher GABA production ability were screened out by paper chromatography, MRS plate with 138 g/L monosodium glutamate (MSG), berthelot colorimetry and high performance liquid chromatography (HPLC) determination. Among them, strain UL-4, obtained by combined UV-LiCl mutagenesis, exhibited the highest GABA production (899.27 mg/L in MRS fortified with 1% MSG and 369.53 mg/L in chickpea milk fortified with 0.2% MSG, which were increased by 64.25% and 30.46% as compared to those of the original strain, respectively). The strain had good genetic stability.

Key words: chickpea milk, lactic acid bacteria, γ-aminobutyric acid, compound mutagenesis