通过外源添加叶酸合成前体对氨基苯甲酸、叶酸途径抑制剂氨甲喋呤扰动叶酸代谢,考察了叶酸对谷氨酸棒杆菌SYPS-062合成L-丝氨酸的影响。实验结果表明,添加对氨基苯甲酸(0~0.4μg/mL)能够促进菌体的生长(最大值为7.8±0.24 g/L),但可显著降低其产酸能力;而添加氨甲喋呤(0~100μg/mL)抑制了谷氨酸棒杆菌SYPS-062的生长,但可提高其单位菌体产酸的能力;代谢通量分析表明,作为调控点的叶酸代谢在SYPS-062生长及积累L-丝氨酸中占主导地位。

This study aimed to investigate the effects of exogenous regulation of cofactor folate on C.glutamicum SYPS-062 growth and L-serine accumulation by adding the precursor(p-aminobenzoate,PABA) or inhibitor(methotrexate) of folate biosynthesis to the medium,respectively.The results indicated that the biomass enhanced and reached a maximum value of 7.8 ± 0.24 g /L,while the concentration of L-serine sharply declined as the concentration of PABA was increased from 0 to 0.4 μg /mL.In contrast,the biomass of C.glutamicum SYPS-062 decreased while the L-serine yield to biomass increased with the increase in the concentration of methotrexate from 0 to 100 μg /mL.Metabolic flux analysis showed that folate metabolism played an important role in cell growth and L-serine accumulation of C.glutamicum SYPS-062.