Halomonas cerina sp. nov., a moderately halophilic, denitrifying, exopolysaccharide-producing bacterium

Microbial Exopolysaccharide Research Group, Department of Microbiology, Faculty of Pharmacy, Campus Universitario de Cartuja, University of Granada, 18071 Granada, Spain Correspondence Victoria Béjar vbejar{at}ugr.es Three bacterial strains were isolated from different saline soils in Spain. The novel strains were moderately halophilic, exopolysaccharide-producing, Gram-negative, non-motile rods. The strains required NaCl and grew best with 7.5–10 % (w/v) NaCl in the medium. They formed wax-coloured colonies, were oxidase-positive and showed respiratory metabolism, using oxygen, nitrate and nitrite as terminal electron acceptors. The novel strains were able to denitrify and did not produce acid from sugars. The DNA G+C contents varied between 62.7 and 66.2 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and sequence signatures of this gene showed that all three novel isolates belonged to the genus Halomonas in the class Gammaproteobacteria and formed an independent phylogenetic line. The most phylogenetically related species were Halomonas alimentaria , Halomonas campaniensis, Halomonas gudaonensis and Halomonas ventosae , with which the novel strains showed 16S rRNA gene sequence similarity values of between 96.3 and 95.2 %. The principal fatty acids of the novel strains were 16 : 0, 18 : 1 7 c , 16 : 1 7 c and 19 : 0 cyclo 8 c . The predominant respiratory lipoquinone was ubiquinone with nine isoprene units (Q-9). The name Halomonas cerina sp. nov. is proposed for these isolates. The type strain is SP4 T (=CECT 7282 T =LMG 24145 T ). Abbreviations: EPS, exopolysaccharide; PHA, poly- β -hydroxyalkanoate The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of strains 15CR, SP4 T and R53 are EF613111 , EF613112 and EF613110 , respectively. A dendrogram of phenotypic characteristics based on the simple-matching coefficient and UPGMA methods is available with the online version of this paper.