Abstract
Γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the central nervous system, has been shown to alleviate various physiological disorders including insomnia, hypertension, depression, and memory loss. Lactic acid bacteria (LAB), recognized as safe GABA producers, have attracted increasing attention. This study aimed to screen GABA-producing LAB from naturally fermented dairy products and evaluate their probiotic potential, antioxidant and neuromodulatory activities, while optimizing GABA production. GABA-producing LAB were screened using the Berthelot method and thin-layer chromatography. The safety of Lactiplantibacillus plantarum SY1 was assessed through hemolysin production and drug sensitivity tests. L. plantarum SY1 demonstrated high tolerance to acidic conditions and low bile salt concentrations, along with significant antioxidant capacity (49 ± 0.2% DPPH radical scavenging rate, 86.1 ± 0.14% hydroxyl radical scavenging rate, and 32.7 ± 1.6% superoxide radical anion scavenging rate). In vivo experiments revealed that L. plantarum SY1 extended the lifespan of C. elegans N2, enhanced oxidative stress resistance, and delayed paralysis in transgenic C. elegans (CL4176) by 23.53%. Through OFAT strategy and RSM optimization, GABA production reached 1.49 g/L under optimal conditions (37℃, pH 4.44, 96 h fermentation, and 4.16% inoculum). These findings demonstrate that L. plantarum SY1 is a promising GABA-producing strain with antioxidant and neuromodulatory effects, suggesting its potential as an anti-aging and neuroprotective probiotic.