Halomonas korlensis sp. nov., a moderately halophilic, denitrifying bacterium isolated from saline and alkaline soil

Abstract

Five Gram-negative, rod-shaped, moderately halophilic and denitrifying strains, designated XK1(T), XK2, XK3, XK4 and XK5, were isolated from a saline and alkaline soil in Korla, north-western China. These isolates could grow anaerobically using either nitrate or nitrite as terminal electron acceptors and produced gas from nitrate vigorously. A comparison and phylogenetic analysis of 16S rRNA gene sequences placed these isolates in the genus Halomonas within the family Halomonadaceae. The isolates shared the highest 16S rRNA gene sequence similarities with Halomonas ventosae Al12(T )(95.6 %), Halomonas alimentaria YKJ-16(T) (95.5 %) and Halomonas shengliensis SL014B-85(T) (95.2 %) (values determined by mega 3.1; direct comparison results with GenBank were even lower, not >/=94 %). Sequence similarities with other recognized species were below 95.0 %, far below the 97.0 % threshold generally accepted for the delineation of separate species. BOX-PCR fingerprinting and DNA-DNA hybridization showed high similarities among the five strains which indicated they were members of the same species. The major fatty acids were C(18 : 1)omega8t, C(16 : 0) and C(18 : 1)omega7t. The DNA G+C content was 65.3 mol%. All the results of the phenotypic and genetic analyses supported the hypothesis that the five new strains represent a novel species within the genus Halomonas, for which the name Halomonas korlensis sp. nov. is proposed. The type strain is XK1(T) (=CGMCC 1.6981(T)=DSM 19633(T)).