Biotechnological production of chondroitin

Disclosed is a recombinant microorganism producing chondroitin, defined as a linear glycosaminoglycan constituted by alternating residues of D-glucuronic acid (GlcUA) and N-acetyl-D-galactosamine (GalNAc) bound by beta-1-3 (GlcUA to GalNAc) and beta-1-4 (GalNAc to GlcUA) bonds, characterised in that in said microorganism the kfoE gene originally present which encodes an enzyme responsible for the addition of fructose residues to the linear chondroitin backbone is inactivated by deletion or substitution entirely or in part of said gene or disruption by insertion of an additional nucleotide sequence and wherein said kfoE gene encodes a protein selected from the group consisting of: a protein comprising the amino acid sequence of SEQ ID No: 2 (as defined in the specification); a protein comprising the amino acid sequence of SEQ ID No: 2 (as defined in the specification) modified by deletion, substitution, or insertion of one or more amino acids, and having a fructosyl-transferase activity; and a protein comprising an amino acid sequence having homology of at least 50% with the amino acid sequence of SEQ ID No: 2 (as defined in the specification) and having a fructosyl-transferase activity.