Isolation and Screening for γ-Aminobutyric Acid-Producing Lactic Acid Bacteria from Traditional Fermented Foods in Kashgar

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 1000 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.