Anaeromicrobium sediminis gen. nov., sp. nov., a fermentative bacterium isolated from deep-sea sediment.

A novel anaerobic, mesophilic, heterotrophic bacterium, designated strain DY2726DT, was isolated from West Pacific Ocean sediments. Cells were long rods (0.5-0.8 µm wide, 4-15 µm long), Gram-positive and motile by means of flagella. The temperature and pH ranges for growth were 25-40 °C and pH 6.5-9.0, while optimal growth occurred at 37 °C and pH 7.5, with a generation time of 76 min. The strain required sea salts for growth at concentrations from 10 to 30 g l-1 (optimum at 20 g l-1). Substrates used as carbon sources were yeast extract, tryptone, glucose, cellobiose, starch, gelatin, dextrin, fructose, fucose, galactose, galacturonic acid, gentiobiose, glucosaminic acid, mannose, melibiose, palatinose and rhamnose. Products of fermentation were carbon dioxide, acetic acid and butyric acid. Strain DY2726DT was able to reduce amorphous iron hydroxide, goethite, amorphous iron oxides, anthraquinone-2,6-disulfonate and crotonate, but did not reduce sulfur, sulfate, thiosulfate, sulfite or nitrate. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain DY2726DT was affiliated to the family Clostridiaceae and was most closely related to the type strains of Alkaliphilus transvaalensis (90.0 % similarity) and Alkaliphilus oremlandii (89.6 %). The genomic DNA G+C content was 33.4 mol%. The major cellular fatty acids of strain DY2726DT were C16 : 1, C14 : 0 and C16 : 0. On the basis of its phenotypic and genotypic properties, strain DY2726DT is suggested to represent a novel species of a new genus in the family Clostridiaceae, for which the name Anaeromicrobium sediminis gen. nov., sp. nov. is proposed. The type strain of Anaeromicrobium sediminis is DY2726DT (=JCM 30224T=MCCC 1A00776T).