Sunxiuqinia elliptica gen. nov., sp. nov., a member of the phylum Bacteroidetes isolated from sediment in a sea cucumber farm.

Three novel aerobic, elliptic bacteria, designated DQHS4(T), DQHS8 and DQHS15, were isolated from sediment of a seashore pond for sea cucumber culture in Jimo, Qingdao, on the east coast of China. Cells were Gram-, oxidase- and catalase-negative. All three strains grew at 15-42 °C, pH 5-9 and NaCl concentrations between 0.5 and 10%. DNA-DNA hybridization experiments revealed high (>85%) relatedness among the three novel isolates and suggested that the strains constitute a single species. Comparative 16S rRNA gene sequence analysis indicated that these bacteria had less than 90% similarity to all described species of the phylum Bacteroidetes; the closest relative of the three isolates was Prolixibacter bellariivorans F2(T), sharing only 89.6% sequence similarity. The major cellular fatty acids were iso-C(17:0) 3-OH (19.8-20.0%), iso-C(15:0) (16.9-17.3%), anteiso-C(17:1) B and/or iso-C(17:1) I (7.4-8.7%), C(17:0) 2-OH (8.4%), anteiso-C(15:0) (8.2-8.6%) and C(17:1)ω6c (5.6-6.0%). The major respiratory quinone was menaquinone-7 (MK-7) and the DNA G+C content was 41.8-43.5 mol%. Based on the distinct phylogenetic position and the combination of genotypic, phenotypic and chemotaxonomic characteristics, these three strains were considered to represent a novel species of a new genus in the phylum Bacteroidetes, for which the name Sunxiuqinia elliptica gen. nov., sp. nov. is proposed. The type strain of Sunxiuqinia elliptica is DQHS4(T) (=CGMCC 1.9156(T) =NCCB 100301(T) =LMG 25367(T)).