Shewanella gelidii sp. nov., isolated from the red algae Gelidium amansii, and emended description of Shewanella waksmanii.

Abstract

A novel Gram-stain-negative, straight or slightly curved rod-shaped, non-spore-forming, facultatively anaerobic bacterium with a single polar flagellum, designated RZB5-4T, was isolated from a sample of the red algae Gelidium amansii collected from the coastal region of Rizhao, PR China (119.625° E 35.517° N). The organism grew optimally between 24 and 28 °C, at pH 7.0 and in the presence of 2-3 % (w/v) NaCl. The strain required seawater or artificial seawater for growth, and NaCl alone did not support growth. Strain RZB5-4T contained C16 : 1ω7c and/or C16 : 1ω6c, C16 : 0 and iso-C15 : 0 as the dominant fatty acids. The respiratory quinones detected in strain RZB5-4T were ubiquinone 7, ubiquinone 8, menaquinone 7 and methylmenaquinone 7. The polar lipids of strain RZB5-4T comprised phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamine, one unidentified glycolipid, one unidentified phospholipid and one unknown lipid. The DNA G+C content of strain RZB5-4T was 47 mol %. Phylogenetic analysis based on 16S rRNA and gyrase B (gyrB) gene sequences showed that strain RZB5-4T belonged to the genus Shewanella, clustering with Shewanella waksmanii ATCC BAA-643T. Strain RZB5-4T exhibited the highest 16S rRNA gene sequence similarity value (96.6 %) and the highest gyrB gene sequence similarity value (80.7 %), respectively, to S. waksmanii ATCC BAA-643T. On the basis of polyphasic analyses, strain RZB5-4T represents a novel species of the genus Shewanella, for which the name Shewanella gelidii sp. nov. is proposed. The type strain is RZB5-4T (=JCM 30804T=KCTC 42663T=MCCC 1K00697T).