A modular metabolic engineering for Escherichia coli was designed for efficient production of β-nicotinamide mononucleotide (β-NMN). First, eight enzymes involved in the shunt metabolic pathways of nicotinamide (NAM) and β-NMN were inactivated to reduce the additional consumption of precursors and products by chassis cells. Second, by introducing BcNaiP, BmPnuC, 5-phosphoribosyl-1-pyrophosphate synthetase (Prs) and nicotinamide phosphoribosyl transferase (Nampt) and deleting the regulatory protein PurR, an engineered strain N12’ was obtained, which could accumulate 0.34 g/L β-NMN in shake-flask fermentation. Then, we found that the Nampt enzyme from Comamonadaceae bacterium had higher activity and caused less burden on the chassis cells. By further strengthening the expression levels of BmPnuC and Prs, the β-NMN titer of the engineered strain N18 was increased to 1.36 g/L in shake-flask fermentation. Finally, after fed-batch fermentation for 38 h, the β-NMN titer reached 10.2 g/L, and the molar conversion rate of NAM to β-NMN was 74.5%. This engineered strain has the advantages of clear genetic background, no nutritional defects, and no need for induction and therefore, has a good prospect for industrial application.

β-Nicotinamide mononucleotide (NMN) is present in all organisms and has attracted widespread attention as a nutritional supplement and pharmaceutical product for the treatment of various diseases, such as Alzheimer’s disease, cancer, aging, and vascular dysfunction. Chemical synthesis is the major method for producing NMN, but it faces challenges such as complex synthesis routes, harsh reaction conditions, difficulties in chiral separation of products, and the use of organic solvents, resulting in high product price and limited applications. In contrast, biosynthesis, with its significant advantages of non-toxicity, mild processing conditions, high substrate specificity, strong product selectivity, and high conversion efficiency, has gradually become an ideal alternative for NMN production. NMN is biosynthesized mainly from niacinamide, nicotinamide riboside, niacin, or glucose through different metabolic pathways, and the key enzymes involved include nicotinamide phosphoribosyltransferase, nicotinamide riboside kinase, and NMN synthase. This article focuses on the latest progress in the enzymatic and microbial production of NMN, including the selection and modification of key enzymes, the design of enzymatic cascade reaction, the immobilization of enzymes, the construction of cell factories, and optimization strategies for the fermentation process. In addition, the biosynthesis technologies for NMN derivatives nicotinamide riboside (NR) and nicotinamide adenine dinucleotide (NAD⁺) are reviewed. These studies will provide references for the development of low-cost, high-efficiency methods for the production of NMN and its derivatives.