Halomonas daqiaonensis sp. nov., a moderately halophilic, denitrifying bacterium isolated from a littoral saltern

Abstract

Two novel gram-negative, oxidase- and catalase-positive, rod-shaped bacterial strains, designated YCSA28(T) and YCSA39, were isolated from sediment of Daqiao saltern, Jimo, Qingdao, on the east coast of China. The two strains grew optimally at 28-30 °C, at pH 7.5 and in the presence of 7-8 % (w/v) NaCl. They were assigned to the genus Halomonas, class Gammaproteobacteria, based on 16S rRNA gene sequence analysis. The major cellular fatty acids of the two strains were C(18 : 1)ω7c (42.9 %), C(16 : 0) (23.1 %) and C(16 : 1)ω7c/ω6c (18.0 %), and Q-9 was the major ubiquinone. The G+C content of the DNA of strains YCSA28(T) and YCSA39 was 63.7 and 63.9 mol%, respectively. The predominant respiratory lipoquinone, cellular fatty acid profiles and DNA G+C content of strains YCSA28(T) and YCSA39 were consistent with those of recognized species of the genus Halomonas. Levels of DNA-DNA relatedness between strains YCSA28(T) and YCSA39, between YCSA28(T) and Halomonas ventosae Al12(T), and between YCSA39 and H. ventosae Al12(T) were 95, 45 and 50 %, respectively. Together, these data indicated that strains YCSA28(T) and YCSA39 represent a single novel species of the genus Halomonas, for which the name Halomonas daqiaonensis sp. nov. is proposed. The type strain is YCSA28(T) ( = CGMCC 1.9150(T) = NCCB 100305(T) = MCCC 1B00920(T)).