关键词: γ-氨基丁酸, 布氏乳杆菌, 响应面法, 发酵蔬菜, 优化

Abstract: Two Lactobacillus buchneri strains, S37 and J68, with great ability to produce γ-aminobutyric acid (GABA) had been isolated from Chinese traditional fermentable vegetables in our previous study. In this study, in order to further improve their GABA production ability, the fermentation conditions were optimized. The results showed that the optimal fermentation conditions for the two strains were as follows: time of 72 h, temperature of 35 ℃, L-monosodium glutamate (L-MSG) concentration of 400 mmol/L, and initial pH of 5.0. Under these conditions, the GABA yields for the two strains were 233.9 and 159.3 mmol/L, respectively, and the L-MSG conversion rates were 58.5% and 39.8%, respectively. The one-factor-at-a-time experiments demonstrated that folic acid, L-cysteine and manganese chloride significantly enhanced the GABA production of the two strains. The addition levels of these compounds were optimized to be 8.37 mg/L, 0.94 g/L and 0.60 g/L for strain S37, and 10.16 mg/L, 0.97 g/L and 0.60 g/L for strain J68, respectively by response surface methodology, resulting in GABA yields of 312.6 and 251.2 mmol/L and L-MSG conversion rates of 78.2% and 62.8%, respectively.

Key words: γ-aminobutyric acid, Lactobacillus buchneri, response surface methodology, fermented vegetable, optimization