关键词: 发酵食品, 乳酸菌, γ-氨基丁酸（GABA）, 高效液相色谱仪（HPLC）法, 分子鉴定

Abstract: Gamma-aminobutyric acid (GABA) exhibits a range of physiological benefits, such as lowering blood pressure, alleviating anxiety, and enhancing sleep quality. Lactic acid bacteria, widely regarded as safe microbial strains, offer a promising and advantageous platform for the production of GABA. This study aims to explore the probiotics that produce GABA in traditional fermented foods from the Kashgar region. 38 bacterial strains were isolated from three distinct types of fermented foods，Gram-positive strains and calcium-dissolving bacteria was preliminary identified using the calcium-dissolving halo assay and Gram staining, these selected strains were subsequently cultured in a medium supplemented with 1% monosodium glutamate (MSG). Strains with higher GABA production were initially screened out by paper chromatography, followed by secondary screening with high-performance liquid chromatography (HPLC). Ten GABA-producing strains were identified, with GABA content ranging from 616.27 to 774.47 mg/L and substrate conversion rates of 37.48–51.8%. The strains were identified using morphological, colony characteristics, physiological-biochemical, and molecular biological methods, and compared with relevant sequences from GenBank. The results identified strains JR5, JR10, JR11, and JR19 as Lactobacillus sanfranciscensis, strains MN4, MN11, MN18, and MN24 as Lacticaseibacillus paracasei, and strains Y13 and Y15 as Limosilactobacillus fermentum.

Key words: Fermented foods, Lactic acid bacteria, Gamma-aminobutyric acid (GABA), High-performance liquid chromatography (HPLC), Molecular identification