The present invention relates to a host cell, which comprises under the control of a heterologous promoter a polynucleotide comprising a nucleotide sequence encoding a polypeptide capable of synthesizing a polysaccharide consisting of a dimeric repeating unit as well as to a vaccine composition comprising such host cell. Furthermore, either such host cell or a polypeptide expressed by such host cell is used for the production of a polysaccharide consisting of a dimeric repeating unit which may be used as a glycoconjugate vaccine.