Robertkochia aurantiaca sp. nov., and Robertkochia flava sp. nov., two potential quinate- and catechol-degrading bacteria isolated from tidal-flat sediments

Abstract

Two Gram-negative-strains, 3YJGBD-33^T and 3YJGBD-35^T were isolated from tidal flat sediment in Daebudo, Republic of Korea. The isolates are non-motile, and long rods. Both strains are oxidase-positive and grew in the range of 15–45 °C (optimum, 40 °C) and pH 7–8 (optimum pH 8.0). Growth was observed in the salinity range of 1–6%, with optimum growth at 4.0% for strain 3YJGBD-33^T and 3.0% for strain 3YJGBD-35^T. According to the NCBI 16S ribosomal RNA sequences database the strain 3YJGBD-33^T and 3YJGBD-35^T showed the highest 16S rRNA gene similarity with Robertkochia marina CC-AMO-30D^T (97.0% and 98.4%), Robertkochia sediminum 1368^T (96.4% and 98.3%) and Robertkochia solimangrovi CL23^T (96.0% and 96.5%). The major respiratory quinone is MK-6. The polar lipid profile consists of phosphatidylethanolamine, three aminolipids and two unidentified lipids. The major cellular fatty acids for strains 3YJGBD-33^T and 3YJGBD-35^T were iso-C_15:0, iso-C_15:1 G and iso-C_17:0 3-OH. The draft genome of strains 3YJGBD-33^T and 3YJGBD-35^T are 3.4 Mbp and 3.5 Mbp in size with 2993 coding genes, 41 tRNAs and 2935 coding genes, 42 tRNAs, respectively. The polyphasic analysis confirms that strains 3YJGBD-33^T and 3YJGBD-35^T belong to the genus Robertkochia and represent novel species, for which the names Robertkochia aurantiaca sp. nov. and Robertkochia flava sp. nov. are proposed. The type strains are 3YJGBD-33^T (= KCTC 82715^T = TBRC 19393^T) and 3YJGBD-35^T (= KCTC 82716^T = JCM 34784^T).