Objective To enhance the biosynthesis efficiency of gamma-aminobutyric acid (GABA) via submerged fermentation by Lactiplantibacillus plantarum.Methods With the activity of whole-cell glutamate decarboxylase (GAD) as an evaluation indicator, the GAD production conditions are optimized through systematic investigation of both fermentation conditions and culture media, and the fermentation process for GABA production is subsequently established based on these optimized conditions.Results The optimal fermentation conditions for GAD production by Lpb. plantarum Y-2 are static culture at 30 ℃ for 48 h in a modified MRS (MMRS) medium containing 10 g/L peptone,10 g/L beef extract, 5 g/L yeast extract, 10 g/L sucrose, 1.0 g/L Tween 80, 4.8 g/L CH₃COONa, 0.03 g/L MnSO₄, and 8 g/L L-monosodium glutamate at pH 6.5. Under these conditions, the activity of whole-cell GAD in per liter of fermentation broth is (83.42±4.37) U, which increases by (88.48±9.87)% compared with that in the MRS medium. The yield of GABA synthesized via fermentation in the MMRS medium reaches (2.27±0.12) g/L, representing a (118.27±11.09)% increase compared with that of fermentation in the MRS medium.Conclusion Optimizing the production conditions of GAD to enhance the GABA fermentation process serves as an effective strategy to boost the GABA yield.