Microbial production of nicotamide riboside

A method for producing nicotinamide riboside (NR), comprising culturing a bacterium cell in a medium under conditions effective to produce NR and recovering NR from the medium and thereby producing NR, wherein the bacterium cell comprises the modification of adding the activity of a heterologous nicotinic acid amidating protein (NadE*) and further comprises at least one modification selected from the group consisting of:

• a) adding or increasing the activity of a nicotinamide adenine dinucleotide (NAD+) hydrolyzing protein;
• b) blocking or reducing the activity of a protein which functions to repress NAD+ biosynthesis by repressing transcription of nadA, nadB, nadC genes or combinations thereof;
• c) blocking or reducing the activity of a protein which functions as a nicotinamide riboside transporter protein;
• d) blocking or reducing the activity of a protein which functions as a nicotinic acid mononucleotide adenyltransferase;
• e) blocking or reducing the activity of a protein which functions as a nicotinamide mononucleotide amidohydrolase;
• f) blocking or reducing the activity of a protein which functions as a purine nucleoside phosphorylase;
• g) adding or increasing the activity of a protein which functions as a nicotinamide mononucleotide hydrolase;
• and
• h) adding or increasing the activity of a protein which functions as a L-aspartate oxidase, a quinolate synthase, a quinolate phosphoribosyltransferase, or combinations thereof.