柠檬酸钠对肌苷发酵过程代谢流分布的调节

Regulation of sodium citrate on metabolic flux distribution of inosine fermentation process

基于物料的质量守恒定律和中间代谢物的拟稳态假设,定量研究了柠檬酸钠对肌苷发酵过程不同时段代谢流分布的影响.结果表明,添加的柠檬酸钠能够抑制存在于EMP途径和TCA循环之间的“碳源溢流”.在24h以后,EMP途径的代谢通量平均降低33%,HMP途径通量平均增加76%,肌苷合成途径通量平均增加77%,最终产苷由17.44g·L-1提高到24g·L-1,增幅达37.6%.

Metabolic flux analysis was used to understand macroscopical characteristics of fermentation process and cellular metabolic regulation. Based on the law of mass conservation and the assumption of pseudo-steady-state for the intermediates in the metabolic pathways, the effect of sodium citrate on the fluxes distribution of inosine fermentation process was quantitatively analyzed. It was revealed that carbon overflow between EMP pathways and TCA cycle could be restrained with the medium supplemented with sodium citrate. After 24 hours, the flux of EMP pathway decreased by 33% averagely, the flux of HMP pathway increased by 76% averagely, and the flux of inosine synthesis pathway increased by 77% on average. The final inosine yield was improved from 17.44 g·L^-1 to 24 g·L^-1 , by an increase of 37.6%.