Proteiniclasticum Aestuarii Sp. Nov., Isolated from Tidal Flat Sediment, and Emended Descriptions of the Genus Proteiniclasticum and Proteiniclasticum Ruminis

A novel bacterium, designated SCR006(T), was isolated from tidal flat sediment from Suncheon Bay, Republic of Korea. Cells of strain SCR006(T) were strictly anaerobic, motile cocci, Gram-reaction-negative, and catalase- and oxidase-negative. Growth was observed at 4-41 degrees C (optimum, 34-37 degrees C), at pH 6.5-10.0 (optimum, pH 7.0-7.5) and in presence of 0-8% NaCl (optimum, 0-2%). Fermentation products of peptone-yeast-glucose medium were acetate and ethanol. Results of phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SCR006(T) had high sequence similarity to Proteiniclasticum ruminis D3RC-2(T) (97.9%), followed by Youngiibacter multivorans DSM 6139(T) (95.9%) and Youngiibacter fragilis 232.1(T) (95.0%). The average nucleotide identity value between strain SCR006(T) and P. ruminis DSM 24773(T) was 72.7%, which strongly supported that strain SCR006(T) reresents a novel species within the genus Proteiniclasticum. The major cellular fatty acids are iso-C-15:0 (27.2%) and anteiso-C-15:0 (16.9%). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two unidentified phospholipids, an unidentified aminolipid and five unidentified lipids. The genomic size was 3.2 Mb with genomic DNA G+C content of 45.6 mol%. The results of 16S rRNA-based and genome-based phylogenetic tree analyses indicated that SCR006(T) should be assigned to the genus Proteiniclasticum. Strain SCR006(T) could be distinguished from P. ruminis D3RC-2(T) by its growth conditions, cell morphology and genomic characteristics. Based on the phenotypic, phylogenetic, genomic and chemotaxonomic features, strain SCR006(T )represents a novel species, for which the name Proteiniclasticum aestuarii sp. nov. is proposed, with the type strain SCR006(T) (=KCTC 25245(T)= JCM 34531(T)).