Enhancing formation of milk oligosaccharides (HMOs) by modifying lactose import in the cell

A genetically engineered cell capable of producing lactose-N-tetrasaccharide (LNT), lactose-N-neotetrasaccharide (LNnT), or LNT and LNnT and wherein the cell

• a) overexpresses one or more lactose permease genes,
• b) expresses a heterologous MFS transporter protein selected from the group consisting of:
• i. Vag with the amino acid sequence according to SEQ ID NO:
• 62, or a functional homologue thereof having an amino acid sequence which is at least 95% identical to the amino acid sequence of SEQ ID NO:
• 62,
• ii. Nec with the amino acid sequence according to SEQ ID NO:
• 66, or a functional homologue thereof having an amino acid sequence which is at least 95% identical to the amino acid sequence of SEQ ID NO 66:
• iii. Fred, with the amino acid sequence according to SEQ ID NO:
• 63, or a functional homologue thereof having an amino acid sequence which is at least 95% identical to the amino acid sequence of SEQ ID NO:
• 63,
• iv. Marc with the amino acid sequence according to SEQ ID NO:
• 64, or a functional homologue thereof having an amino acid sequence which is at least 95% identical to the amino acid sequence of SEQ ID NO:
• 64 and
• v. Bad with the amino acid sequence according to SEQ ID NO:
• 65, or a functional homologue thereof having an amino acid sequence which is at least 95% identical to the amino acid sequence of SEQ ID NO:
• 65, and
• c) expresses two or more glycosyltransferases selected from the group consisting of β-1,3-GlcNAc-transferases, β-1,3-Gal-transferases and β-1,4-gal-transferases, and
• d) expresses one or more polypeptides involved in the biosynthesis of activated sugars.