Metabolic engineering of Escherichia coli for biosynthesis of β‐nicotinamide mononucleotide from nicotinamide

Abstract

The b-nicotinamide mononucleotide (NMN) is a key intermediate of an essential coenzyme for cellular redox reactions, NAD. Administration of NMN is reported to improve various symptoms, such as diabetes and age-related physiological decline. Thus, NMN is attracting much attention as a promising nutraceutical. Here, we engineered an Escherichia coli strain to produce NMN from cheap substrate nicotinamide (NAM) and glucose. The supply of in vivo precursor phosphoribosyl pyrophosphate (PRPP) and ATP was enhanced by strengthening the metabolic flux from glucose. A nicotinamide phosphoribosyltransferase with high activity was newly screened, which is the key enzyme for converting NAM to NMN with PRPP as cofactor. Notably, the E. coli endogenous protein YgcS, which function is primarily in the uptake of sugars, was firstly proven to be beneficial for NMN production in this study. Fine-tuning regulation of ygcS gene expression in the engineered E. coli strain increased NMN production. Combined with process optimization of whole-cell biocatalysts reaction, a final NMN titre of 496.2 mg l -1 was obtained.

Systematic Engineering of Escherichia coli for Efficient Production of Nicotinamide Mononucleotide From Nicotinamide

“…Thus, it is more advantageous to synthesize NMN using nicotinamide. Based on previous reports, 17,19 Excessive intracellular accumulation of NMN might interfere with physiological processes in E. coli. 29 By introducing the NMN transporter, Shoji et al increased the accumulation of extracellular NMN to 6.79 g/L, which is several hundred times that of the previous report.…”

“…Whole-cell catalysis is currently one of the main methods for NMN biosynthesis. , However, the process is relatively complicated and expensive. In the present study, the fermentation method was used for the biosynthesis of NMN with a simple process, high productivity, and high conversion rate, which make it more suitable for industrial production.…”

“…Thus, it is more advantageous to synthesize NMN using nicotinamide. Based on previous reports, , Liu et al increased the yield of NMN by 70.8% by screening exogenous NAMPTs. Shoji et al selected NAMPTs from different sources, and the synthetic amount of NMN increased by 2.4 times.…”

“…coli with the addition of 10 g/L nicotinamide, the titer of NMN was increased up to 15.42 mg/L . Using NAMPT, Liu et al and Maharjan et al achieved a yield of 496.2 and 771.5 mg/L of NMN, respectively, with the whole-cell catalysis method. Shoji et al identified an NMN transporter (BMpnuC) from Bacillus mycoides and significantly improved the titer of NMN (6.79 g/L) by whole-cell catalysis .…”

Directed evolution of phosphite dehydrogenase to cycle noncanonical redox cofactors via universal growth selection platform

“…Our previous work developed nicotinamide mononucleotide (NMN + ), a truncated version of the native nicotinamide cofactors, as an efficient noncanonical redox cofactor 16 , 17 . Compared to other simpler NAD + mimetics, NMN + can be produced renewably using low-cost feedstocks through biosynthetic pathways 12 , 13 , 18 – 20 . More importantly, its polar structural features (particularly the phosphate) offer unique advantages for enzyme design.…”