A new κ-carrageenase gene cgk S was cloned from marine bacterium Shewanella sp. Kz7 by using degenerate and site-finding PCR. The gene was comprised of an open reading frame of 1224 bp, encoding 407 amino acid residues, with a signal peptide of 24 residues. Based on the deduced amino acid sequence, the κ-carrageenase Cgk S was classified into the Glycoside Hydrolase family 16. The cgk S gene was expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity with a specific activity of 716.8 U mg-1 and a yield of 69%. Recombinant Cgk S was most active at 45℃ and p H 8.0. It was stable at p H 6.0–9.0 and below 30℃. The enzyme did not require Na Cl for activity, although its activity was enhanced by Na Cl. Cgk S degraded κ-carrageenan in an endo-fashion releasing tetrasaccharides and disaccharides as main hydrolysis products. A new κ-carrageenase gene cgk S was cloned from marine bacterium Shewanella sp. Kz7 by using degenerate and site-finding PCR. The gene was comprised of an open reading frame of 1224 bp, encoding 407 amino acid residues, with a signal peptide of The cgk S gene was expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity with a specific activity of 716.8 It was stable at p H 6.0-9.0 and below 30 ° C. The enzyme did not require Na Cl for activity, although it did not require Na Cl for activity its activity was enhanced by Na Cl. Cgk S degraded κ-carrageenan in an endo-fashion releasing tetrasaccharides and disaccharides as main hydrolysis products.