柠檬酸钠对L-异亮氨酸发酵及代谢流量分布的影响  

Effects of Sodium Citrate on Metabolic Flux Distributions of L-Isoleucine Fermentation

作　　者：马雷[1,2] 程立坤[2] 徐庆阳[2] 陈宁[2] 

机构地区：[1]天津科技大学电子信息与自动化学院,天津300222 [2]天津科技大学生物工程学院,天津300457

出　　处：《天津科技大学学报》2010年第3期14-18,共5页Journal of Tianjin University of Science & Technology

基　　金：天津市应用基础及前沿技术研究计划(08JCZDJC15400)

摘　　要：分析黄色短杆菌(Brevibacterium flavum)中L–异亮氨酸生物合成途径得知,添加柠檬酸钠利于L–异亮氨酸发酵.通过考察柠檬酸添加量对副产物含量、菌体生物量、菌体比生长速率及L–异亮氨酸产量的影响,得出柠檬酸钠的最适添加量为2.0 g/L.应用代谢流分析方法研究了柠檬酸钠对L–异亮氨酸发酵中后期细胞内代谢流分布的影响.结果表明,在初始发酵培养基中添加2.0 g/L柠檬酸钠后,合成副产物的代谢流量明显减少,EMP途径代谢流从63.34减弱至46.54,而L–异亮氨酸的生物合成代谢流增长至23.28,较添加前提高了5.91%,且产量提高了7.87%.因此,发酵过程中添加柠檬酸钠可有效减少副产物的生成,提高L–异亮氨酸生物合成途径的代谢流量.The biosynthesis metabolism pathway of L-isoleucine in Brevibacteriumflavum was analyzed,and the addition of sodium citrate was beneficial to L-isoleucine fermentation. The effects of sodium citrate on concentration of byproduct, biomass,specific growth rate and yield of L-isoleucine were studied. The optimal addition concentration of sodium citrate was 2.0 g/L. In order to study the effects of sodium citrate on the metabolic flux distributions in Brevibacteriumflavum fermentation during the middle and late period,the metabolic flux analysis of the L-isoleucine production at pseudo steady state was conducted. The results show that the metabolic flux channeled to byproducts is decreased obviously when sodium citrate （2.0 g/L） is added to the fermentation medium. Moreover,with the addition of sodium citrate,the flux channeled to EMP decreases from 63.34 to 46.54. At the same time,the metabolic flux channeled to the L-isoleucine synthesis pathway increases 5.91% and becomes 23.28,and the yield of L-isoleucine increases 7.87%. All of these show that the addition of sodium citrate leads to the decrease of byproducts formation and strengthens the L-isoleucine biosynthesis.

关 键 词：L-异亮氨酸 柠檬酸钠 黄色短杆菌 代谢流分析 

分 类 号：TQ922[轻工技术与工程—发酵工程]