Halomonas litopenaei sp. nov., a moderately halophilic, exopolysaccharide-producing bacterium isolated from a shrimp hatchery.

Two Gram-stain negative, moderately halophilic, exopolysaccharide-producing bacteria, designated strains SYSU ZJ2214T and SYSU XM8, were isolated from rearing water and larvae from shrimp hatcheries, respectively. Cells of the strains were aerobic, motile and short-rod-shaped. They grew at NaCl concentrations of 0.5-22 % (w/v), at 4-45 °C and at pH 6-9. Pairwise comparison of 16S rRNA gene sequences revealed that strains SYSU ZJ2214T and SYSU XM8 were most closely related to Halomonas denitrificans M29T (98.3 and 98.2 % similarity, respectively). Strains SYSU ZJ2214T and SYSU XM8 shared an average nucleotide identity of 99.9 % between them. The DNA G+C contents were calculated at 64.1 % for both strains from the draft genome information. The major cellular fatty acids (>5 %) were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C12 : 0 3-OH, and the predominant respiratory quinone was ubiquinone Q-9. Their main polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, four unidentified phospholipids and three unidentified lipids. On the basis of phenotypic, genotypic and phylogenetic data, strains SYSU ZJ2214T and SYSU XM8 merit recognition as representatives of a novel species of the genus Halomonas, for which the name Halomonas litopenaei sp. nov. is proposed. The type strain is SYSU ZJ2214T (=NBRC 111829T=KCTC 42974T).