苹果酸对L-谷氨酸发酵代谢流迁移的影响

为更全面深入地理解细胞内谷氨酸代谢的调控机制，以黄色短杆菌GDK-9为供试菌株，应用MATLAB软件和代谢流分析方法定量研究添加苹果酸后L-谷氨酸发酵中、后期胞内的代谢流迁移。在L-谷氨酸发酵中、后期添加2．0g／L苹果酸后，合成副产物L-丙氨酸和乳酸的代谢流量明显减少，分别降低了22．1％和16．5％，EMP途径和乙醛酸循环的代谢流分别减少了2．26％和9．09％，HMP途径的代谢流增加了2．26％，而L-谷氨酸生物合成的代谢流从73．59％增长至79．92％，较未添加前提高了6．33％。添加适量苹果酸能使关键节点发生代谢流迁移，提高了L-谷氨酸合成中心代谢途径的代谢流量。

Effects of malate on metabolic flux transfer of L-glutamic acid fermentation

In order to understand the regulating mechanism of L-glutamic acid metabolism, the metabolic flux transfer during the middle and late period with the addition of malate was studied with the linear programming with MATLAB software. When 2.0 g/L of malate was added to the fermentation medium, the metabolic flux of byproducts L-Ala and lactic acid decreased by 22.1% and 16.5%. At the same time, the metabolic channeled to EMP and glyoxyl circle decreased by 2.26% and 9.09%. However, the metabolic flux channeled to HMP increased by 2.26%. The metabolic flux channeled to the L-glutamic acid synthesis pathway increased from 73.59% to 79.92%. The addition of the malate changed the metabolic flux distributions of the key nodes and strengthened the L-glutamic acid biosynthesis.