At present, there are three main methods to produce NMN: chemical synthesis method, fermentation method and enzymatic catalyzed synthesis method.
Chemical synthesis method: Chemical synthesis method is the relatively simple way to produce NMN, and the cost of this method is much lower than the other two methods. Chemical synthesis method usually requires several steps, and the overall yield is not high. The purity of the product could be improved through further separation and purification. NMN has two types of diastereomers: α-NMN and β-NMN. The pure β-NMN cannot be selectively synthesized via chemical synthesis method, and the chiral purity of NMN synthesized through this method is always low. The byproducts produced in this method are not naturally exists in human body, most of them are chemical impurities (mainly chemical solvents etc.). Although the impurities are trace amount, they still might be accumulated in the body, causing the harmful to human body for a long period.
Fermentation method: The product of this method is mainly represented by Shinkowa from Japan. The high technical barriers and the low product yield leads to an expensive price of the product.
Enzyme catalyzed synthesis method: this is what we usually called enzymatic method. This method simulates the metabolic pathway of NMN in human body, express the enzyme in vitro, and realize the enzyme catalysis reaction in vitro to produce NMN. The production process of enzymatic method is the same as in vivo, giving no extra byproducts (purity above 99%). Enzymatic methods can be further divided into one-step enzymatic method and full enzymatic method. One-step enzymatic method is to synthesize NMN through one-step enzymatic catalyzed reaction using chemical synthesized NR as raw material. Full enzymatic method using the core starting material from natural source, which further synthesize NMN by simulating the multi-step enzymatic reaction in vivo. Full enzymatic method does not involve chemical materials, it is safe and has high technical barriers.
Full enzymatic method is a common production method of NMN at present, with high technical barriers. Several key catalytic enzymes are expensive, accounting for about 80% of the cost in the whole production process, but this method is the safest and most efficient way. NMN produced by the full enzymatic method is superior to other production methods in terms of product purity, safety and stability, and it is the first choice of the major manufacturers in the market.