Enzymatic synthesis of high-titer nicotinamide mononucleotide with a new nicotinamide riboside kinase and an efficient ATP regeneration system

Abstract Background ?-Nicotinamide mononucleotide (NMN) is the direct precursor of nicotinamide coenzymes such as NAD + and NADP , which are widely applied in industrial biocatalysis especially involving cofactor-dependent oxidoreductases. Moreover, NMN a promising candidate for medical uses since it considered to be beneficial improving health aged people who usually suffer from an insufficient level . To date, various methods have been developed synthesis NMN. Chemical phosphorylation riboside (NR) depends on excessive phosphine oxychloride delicate temperature control, while fermentation limited by low product titers, making unsuitable industrial-scale production. As result, more efficient process still challenging. Aim This work attempted construct eco-friendly cost-effective biocatalytic transforming chemically synthesized NR into highly value-added Results A new kinase ( Klm- NRK) was identified Kluyveromyces marxianus The specific activity purified NRK 7.9 U·mg –1 protein, ranking highest record among reported NRKs. optimal pH Klm -NRK 7.0 potassium phosphate buffer. retained half after 7.29 h at 50 °C. catalytic efficiencies k cat / K M ) toward ATP were 57.4 s ?1 ·mM 84.4 respectively. In presence external regeneration system (AcK/AcP), much 100 g·L could completely phosphorylated 8 with -NRK, achieving molar isolation yield 84.2% space–time 281 ·day These inspiring results indicated that biocatalyst provides approach bio-manufacturing high titer. Graphical