sp. nov., isolated from Antarctic intertidal sediment produces a novel extracellular polymeric substance.

An exopolysaccharide-producing bacterial strain GW4-15, belonging to the genus , was isolated from intertidal sediment from King George Island, Antarctic. The strain was Gram-stain-negative, aerobic, rod-shaped, non-motile and yellow-pigmented. The strain was able to grow in the presence of 0-2 % (w/v) NaCl (optimum, 0 %), at 4-30 °C (optimum, 20-28 °C) and at pH 5.0-10.0 (optimum, pH 8.0). A phylogenetic tree based on 16S rRNA gene sequences showed that strain GW4-15 formed a lineage within the genus with the closest phylogenetic neighbours NCTC 13525 (98.3 %), G5-32 (97.7 %), LMG 24720 (97.4 %) and HMD1043 (96.9 %). Digital DNA-DNA hybridization values of strain GW4-15 with NCTC 13525, LMG 24720, G5-32 and HMD1043 were 22.8, 22.0, 21.7 and 21.6 %, respectively. The average nucleotide identity values between strain GW4-15 and NCTC 13525 LMG 24720, G5-32 and HMD1043 were 79.3, 78.6, 77.5 and 77.2 %, respectively. The G+C content of the genome was 36.2 mol%. The major phospholipids were phosphatidylethanolamine and aminophospholipid. The predominant menaquinone was MK-6. The major fatty acids were anteiso-C (28.7 %), iso-C 3-OH (15.7 %), iso-C H (10.0 %), iso-C (5.4 %), summed feature 9 (comprising iso-C 9 and/or 10-methyl C; 5.2 %) and iso-C (5.1 %). The monosaccharide composition of the new type of extracellular polymeric of GW4-15 was Glc, GalN, GlcN, Rha, Man and Gal with a molar ratio of 3.14 : 3.83 : 8.38 : 5.16 : 1 : 2.82. Based on phenotypic, phylogenetic and genotypic data, a novel species, sp. nov., is proposed with the type strain GW4-15 (=CGMCC 1.19368=KCTC 92753).