Gan Jiajia, Chen Xiuzhen, He Yongzhi, Pan Chaozhi, Zhang Yanfeng, Dong Zhiyang
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Agric Food Chem. 2024 Dec 25;72(51):28360-28368. doi: 10.1021/acs.jafc.4c10205. Epub 2024 Dec 10.
Nicotinamide mononucleotide (NMN), a key precursor of NAD, is a promising nutraceutical due to its excellent efficacy in alleviating aging and disease. The bioproduction of NMN faces challenges related to incomplete metabolic engineering and insufficient metabolic flux. Here, we constructed an NMN synthesis pathway in BW25113 by deleting the competitive pathway genes and introducing three heterologous genes encoding the key enzymes nicotinamide phosphoribosyltransferase (NAMPT), phosphoribosyl pyrophosphate synthetase and an NMN transporter. Next, the identification of a highly active NAMPT and optimization of gene expression markedly increased the conversion of NAM to NMN, with a titer of 3503.85 mg/L in shake flasks. Furthermore, by facilitating the coutilization of glucose and xylose, more metabolic flux was diverted toward PRPP biosynthesis, resulting in an NMN titer of 15.66 g/L through whole-cell catalysis and 46.66 g/L in a 2-L bioreactor. This represents the highest NMN yield reported to date, exhibiting great potential for initiating sustainable industrial production of NMN.
烟酰胺单核苷酸（NMN）是烟酰胺腺嘌呤二核苷酸（NAD）的关键前体，因其在缓解衰老和疾病方面的卓越功效而成为一种很有前景的营养保健品。NMN的生物生产面临着与代谢工程不完善和代谢通量不足相关的挑战。在此，我们通过删除竞争途径基因并引入三个编码关键酶烟酰胺磷酸核糖转移酶（NAMPT）、磷酸核糖焦磷酸合成酶和一个NMN转运蛋白的异源基因，在BW25113中构建了一条NMN合成途径。接下来，鉴定出一种高活性的NAMPT并优化基因表达，显著提高了烟酰胺（NAM）向NMN的转化率，摇瓶中的产量达到3503.85 mg/L。此外，通过促进葡萄糖和木糖的共利用，更多的代谢通量转向磷酸核糖焦磷酸（PRPP）的生物合成，通过全细胞催化，NMN产量达到15.66 g/L，在2-L生物反应器中达到46.66 g/L。这代表了迄今为止报道的最高NMN产量，显示出启动NMN可持续工业化生产的巨大潜力。
