发酵鹰嘴豆乳产γ-氨基丁酸乳酸菌的复合诱变选育

采用复合诱变的方式提高乳酸菌发酵鹰嘴豆乳产γ-氨基丁酸(γ-aminobutyric acid,GABA)的能力,为开发富含GABA的功能性食品打下基础。以植物乳杆菌M-6作为出发菌株,分别进行紫外、紫外-氯化锂复合诱变,确定紫外照射最佳时间为240 s,氯化锂最佳质量分数为1.25%。采用谷氨酸钠(monosodium glutamate,MSG)平板法、纸层析法、berthelot比色法和高效液相色谱法对突变株的产GABA特性进行检测,筛选到21株GABA产量高于出发菌株的菌株,其中紫外-氯化锂诱变所得突变株UL-4产量最高,在MRSG培养基(含1%MSG)和鹰嘴豆乳(含0.2%MSG)里的产量分别为899.27 mg/L和369.53 mg/L,比出发菌株分别提高64.25%和30.46%,具有良好的遗传稳定性。

Improving γ-Aminobutyric Acid Production of Lactic Acid Bacteria in Chickpea Milk by Compound Mutagenesis

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.