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

Abstract

(Dobson & Franzmann, 1996; Martínez-Cánovas et al., 2004; González-Domenech et al., 2008). The colonies of species of the genus Halomonas are various shades of white and yellow. Species are also characterized by the presence of C 16 : 1 plus C 17 : 0 cyclo, C 16 : 0 , and C 18 : 1 plus C 19 : 0 cyclo as major fatty acids, with ubiquinone 9 (Q-9) as the predominant isoprenoid quinone (Dobson & Franzmann, 1996;Li et al., 2008; González-Domenech et al., 2009). The DNA G+C content of recognized species of the genus Halomonas ranges from 52 mol% (Halomonas venusta) (Akagawa &Yamasato, 1989;Dobson & Franzmann, 1996) to 74.3 mol% (Halomonas ventosae) (Martínez-Cánovas et al., 2004). We isolated two exopolysaccharide (EPS)-producing strains, YCSA28 T and YCSA39, from sediment of a saltern. They were considered to be members of the genus Halomonas based on their 16S rRNA gene sequences. The aim of this work was to determine the exact taxonomic position of strains YCSA28T and YCSA39 based on their phenotypic, phylogenetic and genomic characteristics.Sediment was sampled at Daqiao saltern, Jimo, Qingdao, on the east coast of China (120.82 u E 36.50 u N). Approximately 1 g sediment was suspended in 100 ml sterilized seawater and vortexed for 10 min. Isolates were obtained by plating serial 10-fold dilutions of the suspension onto modified marine agar medium 2216E-S Abbreviations: EPS, exopolysaccharide; PHB, poly-b-hydroxybutyrate.3These authors contributed equally to this work.

Microorganisms and Their Metabolic Capabilities in the Context of the Biogeochemical Nitrogen Cycle at Extreme Environments

“…Related to extreme archaea, denitrification has been described in several species of halophilic archaea [ 39 , 119 , 120 , 121 ] as well as in the thermophilic archaeon Pyrobaculum aerophilum [ 122 , 123 , 124 ]. A few examples of anaerobic denitrification have also been reported from moderately halophilic bacteria [ 125 , 126 , 127 ]. The enzymes catalyzing anaerobic denitrification in extremophilic archaea and bacteria have been characterized from a biochemical point of view (mainly respiratory nitrate and nitrite reductases) and share some structural features [ 39 , 128 , 129 ].…”

Halomonas piezotolerans sp. nov., a multiple-stress-tolerant bacterium isolated from a deep-sea sediment sample of the New Britain Trench

“…After incubation for 24 h, cultures were diluted by sterile salt solution (3.4 % NaCl) and then spread onto marine agar 2216 (MA; BD Difco) plates containing 0.8 mM H 2 O 2 , which were incubated at 16 °C. After 7 days of incubation, ten small single colonies were picked and transferred to fresh MB liquid media containing different concentrations of H 2 O 2 (1,2,5,10,15,20,25,30, and 35 mM). After 5 days of incubation at 16 °C, strain NBT06E8 T , which could grow best under H 2 O 2 stress was selected, and pure culture was obtained by re-streaking single colonies onto fresh MA plates at 16 °C.…”

“…Gram reactions were performed according to previous procedures [47]. Image of cells of strain NBT06E8 T were obtained with a transmission electron microscope (JEM-1230, jeol) after uranyl acetate staining of cells grown on MA at 30 °C for 30 h. Growth at different temperatures (4,10,15,20,25,30,35,40, 45 and 50 °C) and tolerance to various concentrations of NaCl (0-24 % (intervals of 0.5 %) w/v) were determined based on cultivation in MB liquid medium for 4 days. The pH range for growth from pH 4.0 to 12.0 was tested by adding buffers (pH 4, 100 mM acetate buffer; pH 5.0-6.0, 10 mM MES; pH 7.0 pH 8.0, 10 mM HEPES; pH 9.0-10.0, 10 mM TAPS; pH 11-12, 200 mM potassium chloride buffer) for 4 days.…”

“…A common feature of the genus Halomonas is salt tolerance, many Halomonas strains are able to grow at salinity up to 32.5 % [27]. Some Halomonas species have been recognized as having potential applications in biotechnology owing to their tolerance to heavy metals [10], exopolysaccharide production [28,29], denitrification [30,31] and degradation of aromatic compounds [32]. Here, we present a taxonomic study describing a novel Halomonas species isolated from deep-sea sediment.…”

Halomonas lysinitropha sp. nov., a novel halophilic bacterium isolated from a hypersaline wetland

“…Other enzyme characteristics were analysed according to Krieg and Padgett [6]. Antimicrobial susceptibility tests were carried out on Mueller-Hinton agar plus 5.0 % (w/v) NaCl [7] seeded with a bacterial suspension containing 1.5×10 8 c.f.u. ml −1 using discs (HiMedia) impregnated with various antimicrobial compounds including: ampicillin (10 µg), carbenicillin (100 µg), chloramphenicol (30 µg), gentamicin (10 µg), kanamycin (5 µg), nalidixic acid (30 µg), nitrofurantoin (300 µg), streptomycin (10 µg), polymixin B (100 U), rifampicin (5 µg), cefoxitin (30 µg), amoxicillin (30 µg), bacitracin (10 U), erythromycin (5 µg), penicillin G (10 U), ceftazidime (30 µg), neomycin (30 µg), cephalotin (30 µg), tetracycline (30 µg) and novobiocin (5 µg).…”