中文摘要：

考察了外源添加中间代谢产物、维生素B1和硫酸镁对大肠杆菌发酵产L-苯丙氨酸的影响,结果表明,添加1g/L柠檬酸三钠、1g/L α-酮戊二酸、150mg/L维生素B1及3g/L硫酸镁均对L-苯丙氨酸的合成有利.根据构建的大肠杆菌合成L-苯丙氨酸的生化反应网络,利用代谢通量分析其原因.结果表明,这些物质的添加均可以调节G6P和PEP节点处的代谢通量分布,为L-苯丙氨酸的合成提供更多的前体物质赤藓糖四磷酸（E4P）、磷酸烯醇式丙酮酸（PEP）和还原力NADPH.通过补料分批发酵实验得出,优化后菌体对总葡萄糖的消耗提高了24.49%,菌体终浓度提高了23.50%,L-苯丙氨酸的终浓度提高了62.87%,L-苯丙氨酸的收率提高了30.88%,乙酸的合成降低了56.51%.

英文摘要：

The effect of adding intermediate metabolites, thiamine, magnesium on cell growth and L-phenylalanine production were investigated. The yield of L-phenylalanine （L-phe） improved when 1g/L sodium citrate, 1g/L α-ketoglutarate, 150mg/L thiamine or 3g/L magnesium was added. According to the metabolic network of E.coli YP1617, the reason was acquired by metabolic flux analysis. The addition of them can adjust the metabolic flux distribution of G6Pand PEPnode, which provide erythrose-4-phosphate （E4P）, phosphoenolpyruvate （PEP） and NADPH for L-Phe production. In the optimal fed-batch fermentation, glucose consumption, cell and L-Phe concentrations, the yield of L-Phe was 24.49%, 23.50%, 62.87% and 30.88% higher than the control, respectively. Moreover, acetate production decreased 56.51%.