Harnessing lactic acid bacteria for nicotinamide mononucleotide biosynthesis: a review of strategies and future directions

Abstract

Nicotinamide mononucleotide (NMN), one of the crucial precursors of nicotinamide adenine dinucleotide, has garnered considerable interest for its pharmacological and anti-aging effects, conferring potential health and economic benefits for humans. Lactic acid bacteria (LAB) are one of the most important probiotics, which is commonly used in the dairy industry. Due to its probiotic properties, it presents an attractive platform for food-grade NMN production. LAB have also been extensively utilized to enhance the functional properties of pharmaceuticals and cosmetics, making them promising candidates for large-scale up synthesis of NMN. This review provides an in-depth analysis of various metabolic engineering strategies, including enzyme optimization, pathway rewiring, and fermentation process enhancements, to increase NMN yields in LAB. It explores both CRISPR/Cas9 and traditional methods to manipulate key biosynthetic pathways. In particular, this study discussed future research directions, emphasizing the application of synthetic biology, systems biology, and AI-driven optimization to further enhance NMN production. It provides invaluable insights into developing scalable and industrially relevant processes for NMN production to meet the growing market demand.

Keywords: biosynthesis; lactic acid bacteria; metabolic engineering; microbial fermentation; nicotinamide mononucleotide.

Figure 1

Schematic representation of the functions of NMN. Illustrates the key physiological roles of NMN in cellular processes.

Figure 2

Synthesis methods of NMN. Comparison of chemical synthesis, enzymatic synthesis, and fermentation synthesis of NMN using different substrates.

Figure 3

Schematic diagram of the biosynthesis of NMN using different substrates. zwf, glucose 6-phosphate dehydrogenase; pgi, glucose-6-phosphate isomerase; pgl, 6-phosphogluconolactonase; gnd, 6-phosphogluconate dehydrogenase; rpiA, ribose 5-phosphate isomerase A; rpiB, ribose 5-phosphate isomerase B; prs, phosphoribosyl pyrophosphate synthetase; NAMPT, nicotinamide phosphoribosyl transferase; R5P, ribose 5-phosphate; PRPP, 5-phosphoribosyl-1-pyrophosphate; NAM, nicotinamide; NMN, nicotinamide mononucleotide; PnuC, nicotinamide riboside transporter; NiaP, niacin transporter; FtnadE, NMN synthase from Francisella tularensis; pncC, NMN aminohydrolase; NA, nicotinic acid; NaMN, nicotinic acid mononucleotide; pncA, nicotinamidase; pncB, nicotinic acid phosphoribosyltransferase; NR, nicotinamide riboside; NRK, nicotinamide riboside kinase; RK, ribokinase; amn, AMP nucleosidase; add, adenosine deaminase; Ado1, adenosine kinase derived from Saccharomyces cerevisiae; R1P, ribose 1-phosphate; Adk, adenosine kinase; APRT, adenine phosphoribosyltransferase; ATP, adenosine triphosphate; ADP, adenosine diphosphate; AMP, adenosine monophosphate; PPi, inorganic pyrophosphate; IMP, inosine monophosphate; HPRT, hypoxanthine-guanine phosphoribosyltransferase; UPP, uridine phosphorylase; PyNP, pyrimidine nucleoside phosphorylase; PNP, purine nucleoside phosphorylase; PPM, phosphopentomutase.

Figure 4

Synthetic biology approaches for NMN production in lactic acid bacteria (LAB). The design-build-test-learn (DBTL) framework is a well-established method in metabolic engineering. This diagram illustrates the DBTL cycle applied to NMN biosynthesis in LAB, highlighting key components of each stage. “Design”: selection of suitable hosts for NMN synthesis through systematic analysis. “Build”: modification of the NMN synthesis pathway using the CRISPR/Cas9 system. “Test”: verification of NMN synthesis capacity through fermentation. “Learn”: application of machine learning and statistical methods to identify the relationship between NMN levels and the design parameters.