Biosynthesis of human milk oligosaccharides in engineered bacteria

A method for producing a fucosylated oligosaccharide in a bacterium, comprising

• providing an enteric bacterium, said bacterium comprising a functional β-galactosidase gene, an exogenous fucosyltransferase gene, a mutation in a colanic acid synthesis gene, and a functional lactose permease gene;
• culturing said bacterium in the presence of lactose;
• and
• retrieving a fucosylated oligosaccharide from said bacterium or from a culture supernatant of said bacterium.

A method for producing a 3′-sialyl-3-fucosyllactose (3′-S3FL) in a bacterium,

• said bacterium comprising a functional β-galactosidase gene, an exogenous sialyl-transferase gene, an exogenous fucosyltransferase gene, a GDP-fucose synthesis pathway, a deficient sialic acid catabolic pathway, a sialic acid synthetic capability, and a functional lactose permease gene;
• culturing said bacterium in the presence of lactose;
• and
• retrieving said 3′-S3FL from said bacterium or from a culture supernatant of said bacterium.

A method for producing a 3′-sialyl-3-fucosyllactose (3′-S3FL) in an enteric bacterium,

• said enteric bacterium comprising a functional lacZ gene, an exogenous fucosyltransferase gene, an exogenous sialyltransferase gene, a mutation in an endogenous colanic acid synthesis gene, a functional lactose permease gene, a deficient sialic acid catabolic pathway, and sialic acid synthetic capability;
• culturing said bacterium in the presence of lactose;
• and
• retrieving said 3′-S3FL from said bacterium or from a culture supernatant of said bacterium.