丙酮酸钠促进S腺苷蛋氨酸和谷胱甘肽联合高产及其生理机制

为了考察丙酮酸钠对S-腺苷蛋氨酸(SAM)和谷胱甘肽(GSH)联产发酵的影响,本文通过在不同培养时间向摇瓶中添加不同浓度丙酮酸钠,发现0 h添加2 g/L丙酮酸钠最有利于SAM和GSH生物合成。在该条件下进行分批发酵培养,结果表明:SAM和GSH联产量在27 h时达到最大值402.3 mg/L,比不添加丙酮酸钠的对照提高了35.1%。进一步地,对酵母胞内SAM合成酶、γ-谷氨酰半胱氨酸合成酶、己糖激酶、异柠檬酸脱氢酶的活性以及NADH和ATP含量进行测定,结果发现:丙酮酸钠添加不仅提高了SAM和GSH代谢途径中的关键酶活性,还提高了胞内能量代谢物质的水平,最终提升了SAM和GSH的合成能力,实现了SAM和GSH的联合高产。该研究结果为类似耗能合成化合物的高效生产提供了一种可行的思路。

Sodium pyruvate improves the co-production of S-adenosylmethionine and glutathione and its physiological mechanism

In order to investigate the effect of sodium pyruvate on the biosynthesis of S-adenosylmethionine(SAM) and glutathione(GSH),the addition of different concentrations of sodium pyruvate into medium in flasks during different culture time was carried out. It was found that the addition of 2 g/L sodium pyruvate at 0 h was the optimum condition for the biosynthesis of SAM and GSH. The maximum co-production of SAM and GSH of 402.3 mg/L was obtained at 27 h during batch fermentation under the optimum sodium pyruvate addition strategy,which was increased by 35.1% compared to that of the control without sodium pyruvate addition. Moreover,the assay of methionine adenosyltransferase,γ-glutamylcysteine synthase,hexose kinase and isocitrate dehydrogenase,as well as the determination of intracellular NADH and ATP were conducted. It was indicated that the addition of sodium pyruvate increased not only activities of key enzymes involved in SAM and GSH biosynthesis,but also intracellular levels of energy metabolic substance,which in turn improved the capability of SAM and GSH biosynthesis,and the co-production of SAM and GSH. The results presented in this study would provide one feasible approach for efficient production of analogous chemicals biosynthesized with energy consumption.