Process for the production of fucosylated oligosaccharides

A method for the production of fucosylated oligosaccharides using a genetically modified prokaryotic host cell, the method comprising:

• providing a prokaryotic host cell which has been genetically modified to have:
• (i) reduced or abolished activity of a fructose-6-phosphate-converting enzyme as compared to the activity in an unmodified prokaryotic host cell, wherein the fructose-6-phosphate converting enzyme is selected from the group consisting of phosphofructokinase, glucose-6-phosphate isomerase, fructose-6-phosphate aldolase, a transketolase, and a transaldolase;
• (ii) overexpression of at least one gene encoding an enzyme necessary for the de novo synthesis of GDP-fucose, wherein said at least one gene encoding an enzyme necessary for the de novo synthesis of GDP-fucose is a phosphomannomutase encoding gene, a mannose-1-phosphate guanosyltransferase encoding gene, a GDP-mannose-4,6-dehydratase encoding gene, or a GDP-L-fucose synthase encoding gene;
• and
• (iii) expression of an exogenous gene encoding an alpha-1,2-fucosyltransferase and/or an alpha-1,3-fucosyltransferase;
• and
• cultivating said genetically modified prokaryotic host cell in a cultivation medium comprising at least one carbon and/or energy source selected from one or more of the group consisting of glycerol, succinate, malate, pyruvate, lactate, ethanol, and citrate;
• and
• adding lactose to the cultivation medium;
• wherein the fucosylated oligosaccharide is obtained from the medium in which the host cell is cultivated;
• and
• wherein said genetically modified prokaryotic host cell has an intracellular pool of fructose-6-phosphate that is increased by increasing the activity of a fructose-1,6-bisphosphate phosphatase.