对以腺苷酸(Adenosine monophosphate,AMP)为底物合成β-烟酰胺单核苷酸(β-Nicotinamide mononucleotide,β-NMN)的途径进行了研究。在大肠杆菌(Escherichia coli)BL21(DE3)中构建AMP核苷酶(AMN)与磷酸核糖焦磷酸合成酶(PRS)的共表达及融合表达体系,其中,融合菌株PRS-L4-AMN与烟酰胺磷酸核糖转移酶(NAMPT)构成的双菌催化体系具有较高的催化效率,是三菌混合催化体系的2.42倍。进一步对全细胞催化合成NMN的反应体系进行优化,包括pH、温度、缓冲液、金属离子及菌粉投加量等。结果表明,在优化条件下,反应2 h时NMN产量达到最高,为23.7 mmol/L,总收率达33.4%,实现了NMN的一锅法生物合成。

The pathway for the synthesis of β-nicotinamide mononucleotide (β-NMN) using adenosine monophosphate (AMP) as a substrate is investigated.The co-expression and fusion expression systems for AMP nucleosidase AMN and ribose-phosphate pyrophosphokinase (PRS) are constructed within Escherichia coli BL21(DE3).Of which,the dual bacterial catalytic system composing of fusion strain PRS-L4-AMN and nicotinamide phosphoribosyl transferase (NAMPT) shows a high catalytic efficiency,which is 2.42 times that of the mixed three-bacterial catalytic system.The reaction system for the whole-cell catalytic synthesis of NMN is further optimized,including pH,temperature,buffer,metal ions and bacterial powder dosage,etc.Under the optimized conditions,the highest NMN production,23.7 mmol·L^-1,is obtained when the reaction has performed for 2 h with a total yield of 33.4%,which realizes the one-pot biosynthesis of NMN.

施玲慧(1997-),女,硕士研究生,研究方向为生物催化,623927531@qq.com。