Abstract: γ-aminobutyric acid (GABA) has many physiological benefits, such as lowering blood pressure, alleviating anxiety, and enhancing sleep quality. Lactic acid bacteria, generally regarded as safe, enjoy advantages in the production of GABA. This study aimed to explore probiotics that produce GABA from traditional fermented foods in Kashgar. Altogether, 38 bacterial strains were isolated from three types of fermented foods. Lactic acid bacteria were preliminarily selected using the calcium-solubilizing zone method and Gram staining, identifying Gram-positive bacteria capable of producing calcium-solubilizing zones. These selected strains were then fermented in a medium supplemented with 1 000 mg/L monosodium glutamate (MSG). Through primary screening by paper chromatography and secondary screening with high-performance liquid chromatography, we obtained ten strains that produced GABA at high yield (616.27–774.47 mg/L) with substrate conversion rates of 37.48%–51.79% in the MSG-supplemented medium. Based on morphological, colonial, physiological, biochemical, and molecular biological characteristics as well as comparison with relevant sequences from GenBank, strains JR5, JR10, JR11, and JR19 were identified as Lactobacillus sanfranciscensis, strains MN4, MN11, MN18, and MN24 as Lacticaseibacillus paracasei, and strains Y13 and Y15 as Limosilactobacillus fermentum. This study provides a theoretical foundation and practical basis for the production of GABA using microbial resources from traditional fermented foods Kashgar.

Key words: fermented foods; lactic acid bacteria; γ-aminobutyric acid; high-performance liquid chromatography; molecular identification

摘要： γ-氨基丁酸（γ-aminobutyric acid，GABA）具有降血压、抗焦虑、改善睡眠等多种生理功能。乳酸菌是公认的安全级菌株，利用其生产GABA更具优势。为挖掘喀什地区传统发酵食品中产GABA的优异益生菌，本研究从3 种不同的发酵食品中筛选出38 株细菌，使用溶钙圈法和革兰氏染色法对乳酸菌进行初步筛选，选出产生溶钙圈的革兰氏阳性菌，将其在添加1 000 mg/L谷氨酸钠（monosodium glutamate，MSG）的培养基中进行发酵。通过纸层析法初步筛选出GABA产量较高的菌株，再利用高效液相色谱法复筛并进行定量分析，得到10 株高产GABA菌株，10 株乳酸菌在添加MSG的培养基中发酵后产生的GABA含量为616.27～774.47 mg/L，对底物的转化率为37.48%～51.79%。对这些菌株进行个体形态、菌落特征、生理生化和分子生物学方法鉴定，并与GenBank数据库中的有关序列进行比较，结果显示，菌株JR5、JR10、JR11、JR19为旧金山乳杆菌（Lactobacillus sanfranciscensis），菌株MN4、MN11、MN18、MN24为副干酪乳酪杆菌（Lacticaseibacillus paracasei），菌株Y13、Y15为发酵粘液乳杆菌（Limosilactobacillus fermentum）。该研究为进一步利用喀什地区传统发酵食品中微生物资源进行GABA生产提供了理论基础和实践依据。

关键词: 发酵食品；乳酸菌；γ-氨基丁酸；高效液相色谱法；分子鉴定