Halomonas rifensis sp. nov., an exopolysaccharide-producing, halophilic bacterium isolated from a solar saltern.
A polyphasic taxonomic study was conducted on strain HK31(T), a moderately halophilic bacterium isolated from a solar saltern in Chefchaouen, Morocco. The strain was a Gram-reaction-negative, oxidase-positive rod, which was motile by means of peritrichous flagella. The strain required NaCl for growth and grew in salt concentrations (mixture of sea salts) of 0.5-20 % (w/v) (optimum 5-7.5 %, w/v), at 25-45 °C (optimum 32 °C) and at pH 5-10 (optimum pH 6-9). Strain HK31(T) did not produce acids from sugars and its metabolism was respiratory, using oxygen as terminal electron acceptor. The strain was positive for the accumulation of poly-β-hydroxyalkanoate granules and formed mucoid colonies due to the excretion of an exopolysaccharide. The DNA G+C content was 61.5 mol%. 16S rRNA gene sequence analysis indicated that it belonged to the genus Halomonas in the class Gammaproteobacteria. The most phylogenetically related species was Halomonas anticariensis, with which strain HK31(T) showed a 16S rRNA gene sequence similarity of 96.48 %. Its major fatty acids were C(18 : 1)ω7c, C(16 : 0), C(19 : 0) cyclo ω8c, C(16 : 1)ω7c/iso-C(15 : 0) 2-OH and C(12 : 0) 3-OH and the predominant respiratory lipoquinone was ubiquinone with nine isoprene units (Q-9). Based on the evidence provided in this study, strain HK31(T) (= CECT 7698(T) = LMG 25695(T)) represents a novel species of the genus Halomonas, for which the name Halomonas rifensis is proposed.
Biotechnology and Applied Microbiology Research Group, Department of Biology, Faculty of Sciences, University Abdelmalek Essâadi, BP2121, 93002 Tetouan, Morocco.|Microbial Exopolysaccharide Research Group, Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, 18071 Granada, Spain.
Hakima
H
Amjres
Microbial Exopolysaccharide Research Group, Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, 18071 Granada, Spain.
Victoria
V
Béjar
Microbial Exopolysaccharide Research Group, Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, 18071 Granada, Spain.
Emilia
E
Quesada
Biotechnology and Applied Microbiology Research Group, Department of Biology, Faculty of Sciences, University Abdelmalek Essâadi, BP2121, 93002 Tetouan, Morocco.
Jamal
J
Abrini
Microbial Exopolysaccharide Research Group, Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, 18071 Granada, Spain.
Inmaculada
I
Llamas
D001482:Base Composition; D004269:DNA, Bacterial / Q000235:genetics; D005110:Extracellular Space / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D020632:Halomonas / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D009018:Morocco; D010802:Phylogeny; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D012965:Sodium Chloride / Q000378:metabolism*
D004269:DNA, Bacterial; D005227:Fatty Acids; D011135:Polysaccharides, Bacterial; D012336:RNA, Ribosomal, 16S; D012965:Sodium Chloride