谷氨酸脱羧酶工程菌的发酵工艺及酶学性质

Fermentation and Properties of Glutamate Decarboxylase from Genetically Engineered Strain

对谷氨酸脱羧酶(GAD)工程菌DM201的发酵及转化条件进行优化,分析了发酵过程中异丙基-β-D-巯基半乳糖苷(IPTG)诱导条件、转化体系pH、底物浓度和金属离子等因素对谷氨酸脱羧酶活力的影响。发酵过程中最佳IPTG诱导条件为:浓度0.4mmol/L、时间5h、温度30℃;转化温度45℃,pH=4.0,ρ(L-谷氨酸)≈110g/L,镁离子在50mmol/L和5mmol/L浓度时对谷氨酸脱羧酶酶活有稳定作用,铜锌离子对其酶活的抑制作用显著。

The conditions of fermentation and the transforming process of glutamate decarboxylase （GAD） expressed by genetically engineered strain DM201 were optimized in this paper, with the analysis of factors including the IPTG induction factor during fermentation, pH of transforming system, concentration of substrate and metal ions effecting the enzymatic activity of GAD. It then revealed that the concentration of c （IPTG） = 0. 4 mmol/L, inducing time 5 h, temperature 30 ℃ are optimized in the process of fermentation ; together with the optimal conditions of temperature 45 ℃, initial pH = 4.0,ρ （L-Glutamate） ≈ 110 g/L during the reaction process. Metal ions are effective on the stability of GAD activity such as Mg^2＋ at c（ Mg^2＋ ） = 50 mmol/L and c（Mg^2＋ ） = 5 mmol/L,while Cu^2＋ and Zn^2＋ have obviously an inhibitory effect.