重组酿酒酵母全细胞催化合成烟酰胺单核苷酸

Nicotinamide mononucleotide (NMN), as an important bioactive nucleotide, is widely used in medicine, cosmetics and food fields. Current studies have achieved high yield of NMN in Escherichia coli, however, its application is limited by safety problems. In this study, the GRAS yeast Saccharomyces cerevisiae was chosen as chassis cell to synthesize NMN using economic substrate glucose and nicotinamide (Nam). Firstly, the key enzyme nicotinamide phosphoribosyltransferase (Nampt) was screened and semirationally designed. It was found that the concentration of NMN in yeast expressing the D83N-Nampt mutant derived from chitin reached 413.4 mg/L, which was 24.5 times higher than that of (16.2 mg/L) synthesized by chassis yeast. Then the further metabolism of NMN was weakened and the copy number of Nampt and phosphate ribose pyrophosphate synthase (PRPP synthetase) was increased by using rDNA sequence, and the concentration of NMN was further increased to 603.8 mg/L. Finally, the concentration of NMN reached 1.04 g/L at 1.5 h after optimizing the concentration of whole-cell catalytic substrate. This study provides a strategic reference for efficient synthesis of NMN by Saccharomyces cerevisiae.