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 °C (optimum, 34-37 °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 ).