Leeuwenhoekiella nanhaiensis sp. nov., isolated from deep-sea water.

A novel heterotrophic, aerobic, Gram-stain-negative, rod-shaped and yellow bacterium, designated strain G18(T), was isolated from a water sample collected from the deep South China Sea. Strain G18(T) grew at 4-40 °C (optimum 28-32 °C), at pH 6.0-8.0 (optimum pH 6.5-7.5) and with 0-12 % (w/v) NaCl (optimum 3-4 %). The organism was mesophilic and piezotolerant, its optimal growth pressure was 0.1 MPa, which was lower than that at the depth from which it was isolated. Its optimal growth temperature was higher than that at the depth of its isolation. The predominant cellular fatty acids were C15 : 0iso, C17 : 0iso 3-OH and C15 : 1iso. The major polar lipids were composed of phosphatidylethanolamine, one unknown aminolipid and one unknown polar lipid. The major respiratory quinone was menaquinone 6. The G+C content of the genomic DNA was 35 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain G18(T) clustered with species of the genus Leeuwenhoekiella with validly published names within the family Flavobacteriaceae with 95.9-98.2 % sequence similarity. DNA-DNA reassociation values ranged from 9 to 42 %. Differential phenotypic properties, together with the phylogenetic distinctiveness, suggest that strain G18(T) differs from species of the genus Leeuwenhoekiella with validly published names. On the basis of the polyphasic evidence, strain G18(T) represents a novel species, isolated from deep-sea, of the genus Leeuwenhoekiella for which the name Leeuwenhoekiella nanhaiensis sp. nov. is proposed. The type strain is G18(T) ( = CCTCC AB 2015204(T) = KCTC 42729(T)).