Halomonas pelophila sp. nov., isolated from mud and Halomonas aquatica sp. nov., isolated from marine water

Abstract

Two Gram-negative, catalase- and oxidase-positive, cream-coloured, short rod-shaped, and motile bacterial strains, designated CS7^T and SSM6^T, were isolated from mud and marine water collected in Incheon, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences showed that both strains belonged to the genus Halomonas. Strain CS7^T exhibited the highest 16S rRNA similarity with Halomonas urmiana TBZ3^T (99.0%), while strain SSM6^T exhibited the highest 16S rRNA similarity with Halomonas saccharevitans AJ275^T (98.4%). Strain CS7^T was observed at temperatures ranging from 4 to 44 °C (optimum, 30 °C), at pH levels from 2.0 to 12.0 (optimum, pH 8–9), and in NaCl concentrations of 0–23% (w/v) (optimum, 9%). Strain SSM6^T was observed at temperatures ranging from 4 to 37 °C (optimum, 30 °C), at pH levels from 2.0 to 10.0 (optimum, pH 8–9), and in NaCl concentrations of 0% to 23% (w/v) (optimum, 9%). The DNA G + C content of CS7^T was 67.7 mol%, while that of SSM6^T was 65.1 mol%. Strains CS7^T and SSM6^T were identified to possess phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and diphosphatidylglycerol (DPG) as the major polar lipids. Predominant fatty acids (> 10%) in strain CS7^T were C_16:0, C_12:0 3-OH, summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). Predominant fatty acids (> 10%) in strain SSM6^T were C_16:0, C_12:0 3-OH, cyclo-C_19:0 ω8c, and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). Based on phylogenetic, physicochemical, and biochemical data, CS7^T and SSM6^T represent novel species within the genus Halomonas. They have been designated as Halomonas pelophila sp. nov. (= KACC 23728^T = TBRC 19017^T) and Halomonas aquatica sp. nov. (= KACC 23729^T = TBRC 19018^T).