Lactobacillus reuteri is a new probiotic. It is important to know the metabolism characteristics of L reuteri using glucose and glycerol. This paper focused on the metabolism characteristics of L reuteri CG001 under the conditions of glucose/glycerol co-substrate fermentations with glycerol addition at initial time, log phase and stationary phase, respectively. The results show that the metabolic migration will happen whenever glycerol was added during fermentation. Addition of glycerol at initial time would cause glucose to convert mainly to lactic acid and acetic acid. The net accumulation of NADH in this pathway would be used in pathway of glycerol to 1,3-propanediol (1,3-PD). Addition of glycerol at log phase would also lead to the slow metabolic migration from ethanol pathway to acetic acid pathway. Initially accumulated 3-hydroxypropionaldehyde (3-HPA) would be transformed to 1,3-PD. More 1,3-PD and lactic acid would be produced when glucose is added at 12 h. Addition of glycerol at stationary phase would make L. reuteri to accumulate more 3-HPA, which would cause the cell death at a definite concentration, especially when there is no glucose to maintain the cell activity. It was also observed that the L reuteri can reuse its metabolism product of lactic acid to regulate NADH/NAD during fermentation.%罗伊氏乳杆菌(Lactobacillus reuteri)是一种新型的益生菌,为深入了解该菌代谢葡萄糖和甘油特性,采用发酵初期、对数期、静止期不同甘油添加策略,对发酵罐中L.reuteri CG001利用葡萄糖/甘油共底物发酵过程中代谢产物变化情况进行了探讨.结果表明,无论在何时加入甘油均会引起细胞代谢途径的迁移.初始时加入甘油,葡萄糖主要走乳酸和乙酸途径,净生成的NADH主要用于甘油代谢途径,因此会生成较多的1,3-丙二醇;对数期加入甘油,细胞同样会缓慢从乙醇途径向乙酸途径迁移,并在初期积累一定的3-羟基丙醛,继续加入葡萄糖后3-羟基丙醛迅速转化成1,3-丙二醇,最终发酵液中几乎检测不到3-羟基丙醛;静止期加入甘油,细胞能够积累较多的3-羟基丙醛,较高浓度3-羟基丙醛会导致细胞自身的死亡,同时观察到细胞具有利用自身代谢产物乳酸逆向生成乙酸,从而调节代谢过程中NADH/NAD的能力.
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