Showing papers on "Halomonas published in 2008"

A novel moderately halophilic bacterium for decolorizing azo dye under high salt condition

Abstract: Halomonas sp strain GTW was newly isolated from coastal sediments contaminated by chemical wastewater and was identified to be a member of the genus Halomonas by 16S rDNA sequence analysis and physical and biochemical tests. The optimal decolorization conditions were as follows: temperature 30°C, pH 6.5.0–8.5, NaCl 10–20% (w/v) and the optimal carbon source was yeast exact. The results of experiments demonstrated that the bacteria could decolorize different azo dyes under high salt concentration conditions, and the decolorization rate of five tested azo dyes could be above 90% in 24 h. The exploitation of the salt-tolerant bacteria in the bio-treatment system would be a great improvement of conventional biological treatment systems and the bio-treatment concept.

Halomonas profundus sp. nov., a new PHA-producing bacterium isolated from a deep-sea hydrothermal vent shrimp

Abstract: Aims: The objective of the present work was to describe a new deep-sea, aerobic, mesophilic and heterotrophic bacterium, referenced as strain AT1214, able to produce polyhydroxyalkanoates (PHAs) under laboratory conditions. This bacterium was isolated from a shrimp collected nearby a hydrothermal vent located on the Mid-Atlantic Ridge. Methods and Results: This micro-organism, on the basis of the phenotypical features and genotypic investigations, can be clearly assigned to the Halomonas genus and the name of Halomonas profundus is proposed. Optimal growth occurred between 32 and 37°C at a pH between 8 and 9 and at ionic strength between 20 and 30 g l−1 of sea salts. The G + C content of DNA was 58·6%. This bacterium produced PHAs of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from different carbon sources. Conclusions: The bacterium H. profundus produces PHA of 3HB and 3HV monomers from different carbon sources. Significance and Impact of the Study: PHAs share physical and material properties that suggest them for application in various areas, and are considered as an alternative to nonbiodegradable plastics produced from fossil oils. In this study, we describe a new bacteria isolated from a deep-sea hydrothermal vent with the capability to produce polyesters of biotechnological interest.

Phylogenetic analysis of epiphytic marine bacteria on Hole-Rotten diseased sporophytes of Laminaria japonica

Abstract: During an occurrence of Hole-Rotten Disease of Laminaria japonica in a cultivating farm in Ma Shan Shandong province, China, 42 Gram-negative epiphytic marine bacteria were isolated and purified on Zobell 2216E marine agar medium. Morphological and biochemical characteristics of each isolated bacterium were studied, and molecular identification of bacterial strains was conducted with polymerase chain reaction amplification to 16S rRNA gene sequence analysis. Based on nearly full length of 16S rRNA gene sequence analysis, the isolated strains were bacteria that belong to genus Pseudoalteromonas, Vibrio, Halomonas and Bacillus. The percentage of each group was 61.9%, 28.6%, 7.1% and 2.4% respectively. The results of pathogenicity assay showed that 12 strains could cause the disease symptoms in sporophytes of L. japonica. They belonged to the genera Pseudoalteromonas, Vibrio and Halomonas with 58.3%, 33.3%, 8.3% respectively. The results suggest that these bacteria are the dominant marine bacteria on diseased sporophytes of L. japonica and may be the potential pathogenic bacteria associated with Hole-Rotten Disease of L. japonica.

Engineering of halophilic enzymes: Two acidic amino acid residues at the carboxy‐terminal region confer halophilic characteristics to Halomonas and Pseudomonas nucleoside diphosphate kinases

Abstract: Nucleoside diphosphate kinase from Halomonas sp. 593 (HaNDK) exhibits halophilic characteristics. Residues 134 and 135 in the carboxy-terminal region of HaNDK are Glu–Glu, while those of its homologous counterpart of non-halophilic Pseudomonas NDK (PaNDK) are Ala–Ala. The double mutation, E134A-E135A, in HaNDK results in the loss of the halophilic characteristics, and, conversely, the double mutation of A134E-A135E in PaNDK confers halophilic characters to this enzyme, indicating that the charged state of these two residues that are located in the C-terminal region plays a critical role in determining halophilic characteristics. The importance of these two residues versus the net negative charges will be discussed in relation to the halophilicity of NDK.

Heterotrophic denitrification at extremely high salt and pH by haloalkaliphilic Gammaproteobacteria from hypersaline soda lakes

Abstract: In this paper we describe denitrification at extremely high salt and pH in sediments from hypersaline alkaline soda lakes and soda soils. Experiments with sediment slurries demonstrated the presence of acetate-utilizing denitrifying populations active at in situ conditions. Anaerobic enrichment cultures at pH 10 and 4 M total Na+ with acetate as electron donor and nitrate, nitrite and N2O as electron acceptors resulted in the dominance of Gammaproteobacteria belonging to the genus Halomonas. Both mixed and pure culture studies identified nitrite and N2O reduction as rate-limiting steps in the denitrification process at extremely haloalkaline conditions.

Community of extremely halophilic bacteria in historic Dagong Brine Well in southwestern China

Abstract: The Dagong Brine Well, the earliest man-made brine well in record, located in Zigong, Sichuan, China, had the construction and facilities mainly made of bamboo, wood and stone that are eroded easily by halophiles colonizing in the brine of the well. To better preserve this historic placemark, we initiated an investigation on the microbial community and the diversity of the halophilic bacteria in the brine of Dagong well for the first time. A total of 112 aerobic halophile strains were isolated and characterized according to their phenotype, cellular fatty acids composition and 16S rRNA. Furthermore, the intra specific phylogeny of closely related strains was also screened by PCR fragment length polymorphism of 16S–23S ribosomal RNA intergenic spacer regions (ISR). The result showed that the halophilic isolates found in current study were closely related to the following genera: Planococcus, Halomonas, Halobacillus, Oceanobacillus and Virgibacillus, a lineage of the domain Bacteria. Halomonas and Halobacillus were the dominant genera as represents 27% and 40% of the total isolates, respectively. The distribution of other genera was as follows: Oceanobacillus (18%), Virgibacillus (10%) and Planococcus (5%). The ISR analysis disclosed variation of banding pattern in some isolates related to Oceanobacillus and Halobacillus which was observed with phenotypic and physiological characterizations as well. It was clear that these halophiles have adapted to the special man-made hypersaline environment by the basic physiological evolution during phylogenesis and thus resulted in phenotypic and genotypic diversity in the Dagong Brine Well.

Biotechnological Coproduction of Compatible Solutes and Polyhydroxyalkanoates using the Genus Halomonas

Abstract: An increased usage of poly-β-hydroxyalkanoates (PHA), for instance as bulk biodegradable and biocompatible plastics, will require a cheaper production and downstream processing. If the synthesis of this intracellular biopolyester could be combined with the production of another valuable intracellular product, the economic balance of the process could be improved. It was found that the moderately halophilic bacterium Halomonas elongata simultaneously synthesizes PHA and a protector molecule, called ectoine. Whereas the synthesis of PHA is a response to the shortage of nutrients, the production of ectoine counteracts osmotic imbalances. This behavior is in so far surprising as the conditions of a bi-factorial stress initiate the fast simultaneous synthesis of ectoine and PHA. In the presence of 100 g/L NaCl, Halomonas elongata accumulated up to 50 % w/w PHA and up to 14 % ectoine within 2–3 days under so far non-optimized conditions. Furthermore, it was found that other Halomonas species (e.g. Halomonas halodenitrificans and own isolates of Halomonas halodeneurihalina and Halomonas salina) were able to produce both ectoine and PHA.

A mathematical model for growth and osmoregulation in halophilic bacteria.

Abstract: Many molecular details of the ecophysiology of halophilic bacteria that use compatible solutes to maintain osmotic equilibrium have been examined. We ask whether the details are consistent and complete enough to predict growth and osmoregulation in these bacteria by integrating this information in a mathematical model. Parameterized for the halophilic organism Halomonas elongata, the model predicts the substrate and salt dependence of growth, the uptake of potassium and ectoine and the synthesis of ectoine. It is shown that salt (NaCl) dependence of growth can be modelled by substrate inhibition kinetics. Osmoregulation is known to involve accumulation of both ectoine and potassium glutamate in H. elongata. Using published and newly determined parameters, osmoregulatory models using either direct turgor or two-step (turgor and potassium) signalling are compared. The results are consistent with a role for potassium as a second messenger for hyperosmotic stress. Simulations of osmotic upshifts show a transient overregulation of the intracellular solute levels, as has been previously observed in experiments. A possible adaptive value of this overregulation as ‘pre-emptive’ behaviour in an environment with frequent dry periods leading to steadily increasing osmolarity is proposed. As a result of growth parameter estimation, a maximum P : O value of 2 for H. elongata can be inferred. In conclusion, the model developed here reproduces essential aspects of growth and osmoregulation in halophilic bacteria with a minimal set of assumptions.

Halomonas daqingensis sp. nov., a moderately halophilic bacterium isolated from an oilfield soil.

Abstract: A Gram-negative, moderately halophilic, short rod-shaped, aerobic bacterium with peritrichous flagellae, strain DQD2-30(T), was isolated from a soil sample contaminated with crude oil from the Daqing oilfield in Heilongjiang Province, north-eastern China. The novel strain was capable of growth at NaCl concentrations of 1-15 % (w/v) [optimum at 5-10 % (w/v)]. Phylogenetic analyses based on 16S rRNA gene sequences showed that the novel strain belonged to the genus Halomonas in the class Gammaproteobacteria; the highest 16S rRNA gene sequence similarities were with Halomonas desiderata DSM 9502(T) (98.8 %), Halomonas campisalis A4(T) (96.6 %) and Halomonas gudaonensis CGMCC 1.6133(T) (95.1 %). The major cellular fatty acids of strain DQD2-30(T) were C(18 : 1)omega7c (43.97 %), C(19 : 0 )cyclo omega8c (23.37 %) and C(16 : 0) (14.83 %). The predominant respiratory lipoquinone was ubiquinone with nine isoprene units (Q9). The DNA G+C content was 67.0 mol%. The DNA-DNA hybridization values of strain DQD2-30(T) with the most closely related species of the genus Halomonas were 51.8 %, 28.4 % and 23.5 % for H. desiderata, H. campisalis and H. gudaonensis, respectively. Based on these analyses, strain DQD2-30(T )(=CGMCC 1.6443(T)=LMG 23896(T)) is proposed to represent the type strain of a novel species, Halomonas daqingensis sp. nov.

Halomonas nitroreducens sp. nov., a novel nitrate- and nitrite-reducing species

Abstract: We have carried out a polyphasic taxonomic study of strain 11ST, a halophilic, Gram-negative bacterium that is able to respire on nitrate and nitrite in anaerobiosis. Strain 11ST was isolated from a solar saltern in Cahuil, a region next to Pichilemu (Chile). It grows at NaCl concentrations within the range of 3-20 % w/v (optimum 5-7.5 %), temperatures from 4 to 45 degrees C (optimum 20-32 degrees C) and within a pH range of 5-10 (optimum pH 7-9). Its 16S rRNA gene sequence indicates that it belongs to the genus Halomonas in the class Gammaproteobacteria. Its closest relatives are Halomonas alimentaria, H. denitrificans, H. organivorans and H. ventosae, with the type strains of which our strain showed maximum 16S rRNA gene sequence similarity values of 97.1-98.1 %. Its G+C content is 65.3 mol%. DNA-DNA hybridization studies showed 54.2 % relatedness between strain 11ST and H. alimentaria DSM 15356T and 47.2 % relatedness between strain 11ST and H. organivorans CECT 5995T. Lower DNA-DNA hybridization percentages were obtained against the type strains of other related Halomonas species. Its major fatty acids are C12 : 0 3-OH (5.56 %), iso-C15 : 0 2-OH/C16 : 1 omega 7c (22.30 %), C16 : 0 (27.80 %) and C18 : 1 omega 7c (29.92 %). The proposed name for the novel species is Halomonas nitroreducens sp. nov., with strain 11ST (=CECT 7281T =LMG 24185T) being the type strain.

Optimized conditions for the synthesis of vanillic acid under hypersaline conditions by Halomonas elongata DSM 2581T resting cells

Abstract: During growth on ferulic acid, Halomonas elongata DSM 2581T was capable of promoting the formation of a significant amount of vanillic acid. The products were confirmed by high-performance liquid chromatography and gas chromatography mass-spectrometry analyses. To enhance the formation of vanillic acid and prevent its degradation, a resting-cell method using Halomonas elongata was developed. The growth state of the culture utilized for biomass production, the concentration of the biomass, the amount of ferulic acid that was treated and the reutilization of the biomass were optimized. The optimal yield of vanillic acid (82%) was obtained after a 10-h reaction using 10 mM ferulic acid and 5 g/l of cell pregrown on ferulic acid and harvested at the end of the exponential phase.

Halomonas lutea sp. nov., a moderately halophilic bacterium isolated from a salt lake.

Abstract: A Gram-negative, moderately halophilic bacterium, designated YIM 91125, was isolated from a salt lake in Xinjiang province, north-west China. The isolate grew at salinities in the range 1-20 % (w/v) and at 4-45 degrees C. Optimal growth occurred at 37 degrees C, pH 7.5 and 5-10 % (w/v) NaCl. Cells were short rods motile by means of single polar flagella. The major fatty acids were C-18:1 omega 7c, C-16:0, C-19:0 cyclo omega 8c and C-12:0 3-OH. The DNA G + C content was 60.8 mol%. The predominant respiratory quinone was O.-9. A comparison of 16S rRNA gene sequences revealed its relationship to Halomonas species, its closest neighbours being Halomonas pantelleriensis (95.9 % similarity to the type strain) and Halomonas muralis (95.4 % similarity). On the basis of chemotaxonomic, phylogenetic and phenotypic evidence, strain YIM 91125(T) represents a novel member of the genus Halomonas, for which the name Halomonas lutea sp. nov. is proposed. The type strain is YIM 91125(T) (=KCTC 12847(T) =CCTCC AB 206093(T)).

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 XK1T, 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 Al12T (95.6 %), Halomonas alimentaria YKJ-16T (95.5 %) and Halomonas shengliensis SL014B-85T (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 C18 : 1 ω8t, C16 : 0 and C18 : 1 ω7t. 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 XK1T (=CGMCC 1.6981T=DSM 19633T).

Utilization of arylaliphatic nitriles by haloalkaliphilic Halomonas nitrilicus sp. nov. isolated from soda soils

Abstract: An enrichment culture from saline soda soils, using acetate as carbon and energy source and 2- phenylpropionitrile as nitrogen source (PPN) at pH 10, resulted in the isolation of strain ANL-?CH3. The strain was identified as a representative of the genus Halomonas in the Gammaproteobacteria. The bacterium was capable of PPN utilization as a nitrogen source only, while phenylacetonitrile (PAN) served both as carbon, energy and nitrogen source. This capacity was not described previously for any other haloalkaliphilic bacteria. Apart from the nitriles mentioned above, resting cells of ANL- ?CH3 also hydrolyzed mandelonitrile, benzonitrile, acrylonitrile, and phenylglycinonitrile, presumably using nitrilase pathway. Neither nitrile hydratase nor amidase activity was detected. The isolate showed a capacity to grow with benzoate and salicylate as carbon and energy source and demonstrated the ability to completely mineralize PAN. These clearly indicated a potential to catabolize aromatic compounds. On the basis of unique phenotype and distinct phylogeny, strain ANL-?CH3 is proposed as a novel species of the genus Halomonas—Halomonas nitrilicus sp. nov.

Halomonas salifodinae sp. nov., a halophilic bacterium isolated from a salt mine in China.

Abstract: A Gram-negative, aerobic, motile, halophilic bacterium, designated strain BC7(T), was isolated from a salt mine in north-western China and was subjected to a polyphasic taxonomic characterization. The isolate was able to grow in the presence of 0.5-20 % (w/v) NaCl and at pH 6.0-9.0 and 4-48 degrees C; optimum growth was observed with 3 % (w/v) NaCl and at pH 7.0 and 30 degrees C. Cells were long rods, 0.8-1.2 microm wide and 4.0-6.0 microm long. The major fatty acids were C(18 : 1)omega7c, C(16 : 0) and C(16 : 0)omega7c. The DNA G+C content was 65.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain BC7(T) belonged to the genus Halomonas and showed highest sequence similarity to the type strain of Halomonas pacifica (99.2 %). Levels of DNA-DNA relatedness between strain BC7(T) and H. pacifica CGMCC 1.2314(T) and Halomonas taeanensis DSM 16463(T) were 51 and 38 %, respectively. On the basis of phenotypic and genotypic data, strain BC7(T) is considered to represent a novel species of the genus Halomonas, for which the name Halomonas salifodinae sp. nov. is proposed. The type strain is BC7(T) (=CGMCC 1.6774(T) =JCM 14803(T)).

Halomonas caseinilytica sp. nov., a halophilic bacterium isolated from a saline lake on the Qinghai-Tibet Plateau, China.

Abstract: A halophilic, Gram-negative bacterial strain, designated AJ261T, which was isolated from a soil sample from a salt lake on the Qinghai–Tibet Plateau, was subjected to a polyphasic taxonomic study. The isolate grew optimally in the presence of 3–5 % NaCl and used various carbohydrates as sole carbon and energy sources. The genomic DNA G+C content was 63.0 mol%. The predominant fatty acids were C18 : 1 ω7c, C16 : 0 and C12 : 0. A phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate had the highest sequence similarity with respect to type strains of Halomonas elongata (98.2 %), Halomonas eurihalina (98.1 %) and Halomonas halmophila (97.2 %). The DNA–DNA relatedness of strain AJ261T with respect to H. elongata NBRC 15536T, H. eurihalina CGMCC 1.2318T and H. halmophila DSM 5349T was 42, 25 and 26 %, respectively. Overall, the phenotypic, genotypic and phylogenetic results demonstrate that strain AJ261T represents a novel species within the genus Halomonas, for which the name Halomonas caseinilytica is proposed. The type strain is AJ261T (=CGMCC 1.6773T =JCM 14802T).

Tyrosol degradation via the homogentisic acid pathway in a newly isolated Halomonas strain from olive processing effluents.

Abstract: Aims To isolate a new Halomonas sp. strain capable of degrading tyrosol, a toxic compound present in olive mill wastewater, through the homogentisic acid (HGA) pathway. Methods and results A moderately halophilic Gram-negative bacterium belonging to the Halomonas genus and designated strain TYRC17 was isolated from olive processing effluents. This strain was able to completely degrade tyrosol (2-(p-hydroxyphenyl)-ethanol), a toxic compound found in such effluent. Tyrosol degradation begins by an oxidation to 4-hydroxyphenylacetic acid (HPA), which is then converted into HGA by an HPA 1-monooxygenase, while closest Halomonas species degrade tyrosol through 3,4-dihydroxyphenylacetic acid (DHPA). In the presence of transition metals, HGA underwent a pH-dependent abiotic conversion into benzoquinone acetic acid, then into 2,5-dihydroxybenzaldehyde (gentisaldehyde) and pyomelanin, by oxidative decarboxylation and polymerization, respectively. Conclusions Tyrosol degradation via HGA by the new Halomonas sp. strain TYRC17 was complete in the absence of trace elements. In their presence, HGA was abiotically converted into gentisaldehyde and pyomelanin. Significance and impact of the study This is the first report on tyrosol degradation via the HGA pathway under hypersaline conditions and on the oxidative decarboxylation of HGA into gentisaldehyde. It underlines the importance of the Halomonas genus in the bioremediation of toxic-contaminated sites.

Biological control of Botrytis cinerea on stem wounds with moderately halophilic bacteria

Abstract: Infection of tomato stem wounds by Botrytis cinerea is an important problem which can cause severe economic losses in greenhouse tomato crops. Three moderately halophilic bacteria were tested for their ability to protect pruning wounds from attacks by B. cinerea under growth chamber conditions. The severity of the disease estimated by the length of the rotted stem was used to calculate the area under the disease progress curves (AUDPC). Bacterial antagonists (B1, B2 and B3) were very effective in controlling Botrytis-infection on the tomato stems during the first 6 days and later by the end of the experiment. Plants treated with Bacillus subtilis (B1) had the lowest AUDPC (0). It was followed by B. subtilis (B3) and Halomonas sp. (B2) with AUDPC of 9.8 and 17.02, respectively. While the B1 strain best inhibited grey mold development when applied as young culture (24 h), the B3 strain performed better as an older culture (48 h). In contrast to the results obtained with Bacillus species, the efficacy of the bacterial treatment B2 seems to be independent of the growth phase. The co-cultures with fungal spores and either B. subtilis (B1) or Halomonas sp. (B2) applied as a 24 h bacterial culture completely inhibited the germination of B. cinerea after 24 h at 21°C.

Halomonas sabkhae sp. nov., a moderately halophilic bacterium isolated from an Algerian sabkha.

Abstract: A novel moderately halophilic bacterium belonging to the genus Halomonas was isolated from brine samples collected from Ezzemoul sabkha in north-eastern Algeria The cells of strain 5-3T were Gram-negative, rod-shaped and non-motile The strain was catalase- and oxidase-positive and produced an exopolysaccharide Growth occurred at NaCl concentrations of 5–25 % (optimum at 75 %), at 30–50 °C (optimum at 37–40 °C) and at pH 60–90 (optimum at pH 75) The major fatty acids were C12 : 0 3-OH, C16 : 1 ω7c/iso-C15 : 0 2-OH, C16 : 0, C18 : 1 ω7c and C19 : 0 ω8c cyclo The G+C content of the genomic DNA was 570 mol% (T m) The affiliation of strain 5-3T with the genus Halomonas was confirmed by 16S rRNA gene sequence comparisons The most closely related species was Halomonas halmophila, which showed a 16S rRNA gene sequence similarity of 997 % However, the level of DNA–DNA relatedness between the novel isolate and the related Halomonas species was less than 314 % On the basis of the data from this polyphasic study, strain 5-3T represents a novel species of the genus Halomonas, for which the name Halomonas sabkhae sp nov is proposed The type strain is 5-3T (=CECT 7246T=DSM 19122T=LMG 24084T)

Screening and Identification of a Potential Probiotic in Shrimp,Fenneropenaeus chinensis

Abstract: An experiment was conducted to screen a potential probiotic B12(PP B12) isolated from the midgut of the WSSV(White Spot Syndrome Virus) tolerance shrimp(Fenneropenaeus chinensis).The antagonism of PP B12 to pathogens(Vibrio harveyi and V.parahaemolyticus) and its safety for shrimp(F.chinensis) larvae were evaluated.PP B12 was identified according to its morphological,physiological and biochemical characteristics as well as homology analysis of 16S rDNA sequences.PP B12 can produce chemical substances inhibitory to vibiros pathogen,but cannot produce hemolysin,which is harmful to shrimp.PP B12 was sensitive to antibiotics from inhibitors of β-lactamase,Cefens,Aminoglicosideos and Fluoroquinolonas,but resistant to antibiotics from Macrolideos,Tetraciclinas,and intermediate to Glicopeptideos.It was safe for the shrimp larvae when they were challenged by a high immersion concentration of PP B12 at 107 cfu/ml.Morphology observation showed that PP B12 was gram-negative,rod,motile,nonsporulating,and had yellowish cytochrome.Results of physiological and biochemical characteristics of strain B12 were shown that it was catalase-positive and oxidase-positive,and can ferment glucose,produce amylase,reduce nitrate,but cannot produce gelatinase or utilize malonic acid.A 1508 kb of partial 16S rDNA of PP B12 was sequenced and compared with that of related strains.The results revealed that strain B12 comprised sequences more related to the Halomonas sp.SB J85(98.15%).PP B12 was identified as Halomonas sp.

Disposal of seaweed wakame (Undaria pinnatifida) in composting process by marine bacterium Halomonas sp. AW4

Abstract: A novel marine bacterium, identified as Halomonas sp. AW4 by partial 16S rDNA analysis, was isolated from the seaweeds in Awaji Island, Japan. Strain AW4 grew well even in the wide NaCl concentration ranges of 0-3 mol/L, where it showed an optimal growth in the presence of 0.5 mol/L NaCl. The organic components were reduced to 73.6% of initial dry weight after 168 h of composting by inoculation of AW4. The microbial community structure became complex after 72 h of composting. The initial content of alginate was 35.6%, which decreased to 15.6% after 168 h of composting. The decomposition of alginate mainly occurred at the late stage of composting, suggesting that the microbial community consisting of various types of microorganisms is effective in degrading alginate. The germination of plant Brassica campestris L. indicated the promotion effect of composted wakame.

Halomonas sediminis sp. nov., a new halophilic bacterium isolated from salt-lake sediment in China

Abstract: A novel Gram-negative, slightly halophilic, catalase- and oxidase-positive, obligately aerobic bacterium, strain YIM-C248T, was isolated from a sediment sample collected from a salt-lake in the Qaidam Basin in Qinghai, north-west China. Cells were non-sporulating short rods, occurring singly or as doublets, motile with peritrichous flagella. Growth occurred with 1–15% (w/v) NaCl [optimum 2–4% (w/v) NaCl], at pH 6.0–10.0 (optimum pH 7.5) and at 4–35°C (optimum 25–30°C). The major cellular fatty acids were C18:1 ω7c, C12:0 3-OH, cyclo C19:0 ω8c, C16:0 and C16:1. The predominant respiratory quinone was Q-9 and the genomic DNA G + C content was 58.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM-C248T should be assigned to the genus Halomonas. The sequence similarities between the isolate and the type strains of members of the genus Halomonas were in the range of 92.5–97.5%. The combination of phylogenetic analysis, DNA–DNA hybridization data, phenotypic characteristics and chemotaxonomic differences supported the view that strain YIM-C248T represents a new species of the genus Halomonas, for which the name Halomonas sediminis sp. nov. is proposed, with YIM-C248T (=CCTCC AA 207031 = KCTC 22167) as the type strain.

Polymorphic Halophilic Bacteria and Haloarchaea from Lianyungang Taibei and Yancheng Sanwei Salt Field Soils

Abstract: Halophilic microorganisms play important rules in salt field ecosystem and salt production. In this study, halophilic bacteria and haloarchaea from soils of Lianyungang Taibei and Yancheng Sanwei salt fields were analyzed. The halophilic bacterial and haloarchaeal types from both the soils were similar, but each soil had its distinctive species. A total of 17 halophilic bacteria were identified, among them, Halomonas was found from both the soils, while Pontibacillus and Halobacillus were isolated from Sanwei salt field only. Using uncultured 16S rRNA gene library technology, 13 haloarchaeal soil 16S rRNA genes were identified from both the saline soils. Halobacterium and Haloplanus were found from Taibei salt field, while Halobac- terium, Natronobacterium, Halogeometricum and Haloarcula were identified from Sanwei salt field. Ten haloarchaeal 16S rRNA gene sequences showed 92%~97% identities with the GenBank sequences that ap- pear to represent novel soil haloarchaeal species. This study provides important information that is useful for further investigation and application of halophiles of saline soil fields.

Physiological and biotechnological studies on the microalga Dunaliella, the bacterium Halomonas, and the cyanobacteria Arthrospira and Spirulina.

Abstract: A bacterial isolate and a microalga were identified to the genus level using 16S and 18S rRNA gene sequences respectively andA‚· phylogenetic trees were constructed. The bacterial isolate belonged to the genus Halomonas and it was called Halomonas sp. NAH1, whereas the microalga was confirmed as belonging to the species Dunalie/la salina GGAP 19/30 which was the source of 18S rRNA gene. Glycerol production by three strains of the unicellular microalga Dunalie/la (D. parva 19/9, D. parva 19/10, and D. salina 19/30) was explored. The strains were grown in batch cultures in a range of salinities (0.1 4.0 M NaCI). Both intracellular and extracellular glycerol concentrations were measured. All three strains grew well over the range of salinities with optimum growth for all strains at 0.1 to 0.4 M NaC1. All strains leak significant amounts of glycerol in batch cultures. Significant leakage of glycerol into the growth medium was found to be an intrinsic property of the three strains tested. Two strains of Dunalie/la salina (GGAP 19/18 and 19/30) were grown in batch cultures and aerated with different concentrations of G02. Strain 19/18 accumulated large amounts of ~-carotene under nitrogen limitation whereas the strain 19/30 did not. Halomonas sp. NAH1 grew optimally at 1.0 M NaCI and utilised glucose, glycerol or betaine as the sole source of carbon. Glucose supported the most rapid growth rate. Sensitivity of NAH1 to antibiotics was determined and tetracycline had the most inhibitory effect on growth. The cyanobacteria Arthrospira fusiformis GGAP 1475/8 and Spirulina platensis UTEX LB 2340 were shown to be only slightly halotolerant with optimum growth for S. platensis at 0.1 M NaC1 and for A. fusiformis at 0.5 M NaC1. Phycobiliprotein content was very low in both strains, but very high protein content (92.9% of the dry weight biomass) was obtained for S. platensis. This strain looks very promising for mass cultivation for food and/or feed purposes. Glucosyl-glycerol was found to be the compatible solute in both A. fusiformis and S. platensis.

Isolation and Identification of a Moderately Halophilic Bacterium and Its Bioaugmention in Intensifying High-salty Organic Wastewater Treatment

Abstract: In order to study the application of moderately halophilic bacterium in the hypersaline organic wastewater treatment,a moderately halophilic bacterium YS-1 was isolated from the salty water of a Ludaokou salina of Weihai in China.The polyphasic taxonomy study was conducted by identifying its morphological features by AFM by studying the features of culture,measuring the physiologic-biochemical index and analyzing 16 S rDNA sequence homology.Phylogenetic analysis based on 16 S rDNA gene sequences showed that the closest relative of the strain was Halomonas sp.(AB167061).Experiments of intensifying hypersaline organic wastewater treatmented processing in the SBR demonstrate a significant result. The wastewater salt content of initial wastewater was 12% and the initial COD cr was 1 494 mg/L.After 72h's,the removal efficiency of COD cr achieved 90.0%,and after 120 h,it achieved 98.1%.The experiments also showed that the hypersaline organic wastewater treatment had the feasibility acclimating of halophilic bacteria and running of processing system.