Marinimicrobium koreense gen. nov., sp. nov. and Marinimicrobium agarilyticum sp. nov., novel moderately halotolerant bacteria isolated from tidal flat sediment in Korea

1 Korea Research Institute of Bioscience and Biotechnology, 52 Oeundong, Yusong, Daejeon 305-333, Republic of Korea 2 Environmental Biotechnology National Core Research Center, PMBBRC, Division of Environmental Biotechnology, Gyeongsang National University, 660-701, Republic of Korea 3 Department of Food Science and Technology, Chungbuk National University, Cheongju 361-763, Republic of Korea Correspondence Chang-Jin Kim changjin{at}kribb.re.kr Two moderately halotolerant Gram-negative bacteria were isolated from tidal flat sediment of the South Sea in Korea (the Korea Strait). The strains, designated M9 T and M18 T , were strictly aerobic, rod-shaped and non-spore-forming and motile with a flagellum and their major fatty acids were C 16 : 0 and C 19 : 0 cyclo 8 c . Strains M9 T and M18 T could grow in the presence of up to 13–15 % (w/v) NaCl, but their optimum salt concentrations were relatively low (0–3 %, w/v). The major predominant isoprenoid quinone was Q-8 and the G+C content of the genomic DNA was 57–58 mol%. Phylogenetic analyses and comparative 16S rRNA gene sequence studies revealed that strains M9 T and M18 T formed a phylogenetic lineage distinct from the genus Teredinibacter within the class Gammaproteobacteria and were most closely related to the genera Microbulbifer , Saccharophagus and Teredinibacter , with less than 92·5 % 16S rRNA gene sequence similarity. The level of 16S rRNA gene sequence similarity between the two strains was 96·7 %. On the basis of physiological and phylogenetic properties, strains M9 T and M18 T represent separate species within a novel genus of the class Gammaproteobacteria , for which the names Marinimicrobium koreense gen. nov., sp. nov. (type species) and Marinimicrobium agarilyticum sp. nov. are proposed. The type strains of Marinimicrobium koreense and Marinimicrobium agarilyticum are M9 T (=KCTC 12356 T =DSM 16974 T ) and M18 T (=KCTC 12357 T =DSM 16975 T ), respectively. Published online ahead of print on 25 November 2005 as DOI 10.1099/ijs.0.64075-0. The GenBank accession numbers for the 16S rRNA gene sequences of strains M9 T and M18 T are AY839869 and AY839870 . An electron micrograph of a cell of strain M18 T , a photograph of colonies showing agarolytic activity and details of other properties of the novel isolates are available as supplementary material in IJSEM Online.