Isolation and Characterisation of Gracilimonas aurantiaca sp. nov., A Novel Bacterium Isolated from Tidal-Flat Sediment.

Abstract

A novel bacterium MJW-20^T, was isolated from deep tidal-flat sediment in Gochang, Republic of Korea. The isolate is a bright-orange, Gram-stain-negative, aerobic, non-motile, slow-growing long-rods. The strain MJW-20^T is oxidase, and catalase-positive. The growth is observed at 25-40 °C (optimum, 30 °C) and pH 5-9 (optimum, pH 7.0) in the presence of 0-9% (w/v) NaCl (optimum, 2.0% NaCl). The NCBI 16S ribosomal RNA sequences showed that the strain MJW-20^T is closely affliated with Balneola vulgaris 13IX/A01/164^T (94.6%), Gracilimonas halophila WDS2C40^T (94.5%), Gracilimonas amylolytica LA399^T (94.0%), Gracilimonas rosea CL-KR2^T (93.8%) and Balneola alkaliphila CM41_14b^T (93.3%) from the family Balneolaceae. The major respiratory quinone was MK-7. The major polar lipids identified were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phospholipid (PL) and phosphatidylinositolmannosides (PIMs) for strain MJW-20^T.The major cellular fatty acids of type strain MJW-20^T were C_15:0 iso (32.9%), C_16:1 ω7c/C_16:1 ω6c (11.9%), and C_16:0 10-methyl/C_17:1 iso ω9c (15.9%). The genome length of the type strain MJW-20^T is 3.1 Mbp (DNA G + C content, 44%). It has 2,785 coding genes and 38 tRNAs. The analysis promotes that the average amino acid identity values, average nucleotide identity values, and biochemical, phylogenetic, and physiological characteristics support the genotypic and phenotypic differentiation of strain MJW-20^T from other species of the genus Gracilimonas. Thereupon, the strain MJW-20^T is considered to represent a novel species of the genus Gracilimonas, for which the name Gracilimonas aurantiaca sp. nov. is proposed. The type strain is MJW-20^T (= KCTC 102297^T = JCM 37229^T).