Process for manipulating the level of glycan content of a glycoprotein

A method for manipulating the fucosylated glycan content on a recombinant protein comprising

• inoculating a bioreactor with host cells expressing the recombinant protein,
• culturing the host cells in a serum free, chemically defined cell culture medium;
• wherein the cell culture medium includes from 10 to 100 ppb copper and from 50 to 1000 nM manganese, at pH 7.0,
• harvesting the recombinant protein produced by the host cell,
• wherein the level of afucosylated glycans on the recombinant protein increases compared to the afucosylated glycan level obtained in the same cell culture medium at a lower pH.