Halospeciosus flavus gen. nov., sp. nov. and Haladaptatus caseinilyticus sp. nov., halophilic archaea isolated from saline soil of an inland solar saltern and offshore sediment.

Two novel halophilic archaeal strains (XZGYJ-43T and ZJ1T) were isolated from Mangkang ancient solar saltern (Tibet, PR China) and Zhujiang river inlet (Guangdong, PR China), respectively. The comparison of the 16S rRNA gene sequences revealed that strain XZGYJ-43T is related to the current species of the family Halobacteriaceae (89.2-91.7% similarity) and strain ZJ1T showed 94.7-98.3% similarity to the current species of the genus Haladaptatus. Phylogenetic analyses based on 16S rRNA genes, rpoB' genes and genomes indicated that strain XZGYJ-43T is separate from the related genera, Halocalculus, Salarchaeum and Halarchaeum of the family Halobacteriaceae, and strain ZJ1T tightly clusters with the current species of the genus Haladaptatus. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between strain XZGYJ-43T and the current species of the family Halobacteriaceae were 71-75, 20-25 and 59-68 %, and these values between strain ZJ1T and the current species of the genus Haladaptatus were 77-81, 27-32 and 76-82 %, respectively, clearly below the thresholds for prokaryotic species demarcation. These two strains could be distinguished from their relatives according to differential phenotypic characteristics. The major polar lipids of strain XZGYJ-43T were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), mannosyl glucosyl diether (DGD-1; DGD-PA) and sulphated mannosyl glucosyl diether (S-DGD-1; S-DGD-PA), and those of strain ZJ1T were PA, PG, PGP-Me, DGD-PA, S-DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. Based on phenotypic, phylogenetic and genomic data, strain XZGYJ-43T (=CGMCC 1.13890T=JCM 33735T) represents a novel species of a new genus within the family Halobacteriaceae, and strain ZJ1T (=CGMCC 1.18785T=JCM 34917T) represents a novel species of the genus Haladaptatus, for which the names Halospeciosus flavus gen. nov., sp. nov. and Haladaptatus caseinilyticus sp. nov. are proposed, respectively.

Halomicrococcus gelatinilyticus sp. nov. and Halosimplex aquaticum sp. nov., halophilic archaea isolated from saline soil and an inland solar saltern.

Two extremely halophilic archaeal strains, GSLN9T and XZYJT29T, were isolated from the saline soil in different regions of western China. Both strains GSLN9T and XZYJT29T have two 16S rRNA genes with similarities of 95.1 and 94.8 %, respectively. Strain GSLN9T was mostly related to the genus Halomicrococcus based on 16S rRNA (showing 91.0-96.0 % identities) and rpoB' genes (showing 92.0 % identity). Strain XZYJT29T showed 92.1-97.6 % (16S rRNA gene) and 91.4-93.1 % (rpoB' gene) sequence similarities to its relatives in the genus Halosimplex, respectively. The polar lipid profile of strain GSLN9T included phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulphate (PGS), sulphated mannosyl glucosyl diether (S-DGD-1) and sulphated galactosyl mannosyl glucosyl diether (S-TGD-1), mostly similar to that of Halomicrococcus hydrotolerans H22T. PA, PG, PGP-Me, S-DGD-1 (S-DGD-PA), S2-DGD, S-TGD-1 and an unidentified glycolipid were detected in strain XZYJT29T; this polar lipid composition is similar to those of members of the genus Halosimplex. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between these two strains and their relatives of the genera Halomicrococcus and Halosimplex were no more than 82, 27 and 80 %, respectively, much lower than the thresholds for species demarcation. Other phenotypic characterization results indicated that strains GSLN9T and XZYJT29T can be differentiated from the current species of the genera Halomicrococcus and Halosimplex, respectively. These results revealed that strains GSLN9T (=CGMCC 1.15215T=JCM 30842T) and XZYJT29T (=CGMCC 1.15828T=JCM 31853T) represent novel species of Halomicrococcus and Halosimplex, for which the names Halomicrococcus gelatinilyticus sp. nov. and Halosimplex aquaticum sp. nov. are proposed.

Genome-based taxonomy of genera Haloarcula and Halomicroarcula, and description of six novel species of Haloarcula.

The genera Haloarcula and Halomicroarcula are the most closely related genera within the family Haloarculaceae (class Halobacteria). The respective 16S rRNA genes of type strains from the genus Haloarcula showed 94.7-96.5% similarities to their homologous genes of type strains from the genus Halomicroarcula. The Haloarcula species showed 89.3-92.8% rpoB' gene similarities to Halomicroarcula species. These similarities were higher than the proposed genus boundary. Phylogenomic analysis revealed that these two genera formed a tight cluster separated from Halomicrobium with high bootstrap confidence. The average amino acid identity (AAI) values among Haloarcula and Halomicroarcula were 70.1-74.5%, higher than the cutoff value (67.0%) to differentiate the genera Haloarcula and Halomicroarcula from Halomicrobium. These results indicated that the genus Halomicroarcula should be merged with Haloarcula. Then, six novel species are described based on strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T isolated from coarse sea salt, marine solar saltern, and salt lake (China). These six strains formed separate clades (90.1-99.3% 16S rRNA and 89.0-94.9% rpoB' gene similarities) and then clustered with current Haloarcula and Halomicroarcula species (89.4-99.1% 16S rRNA and 87.6-95.0% rpoB' gene similarities), as revealed by phylogenetic analyses. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and AAI values among these six strains and current Haloarcula and Halomicroarcula species were 76.2-89.8%, 25.3-46.0%, and 70.3-89.7%, respectively, clearly below the species demarcation threshold. These six strains were distinguished from current Haloarcula and Halomicroarcula species according to differential phenotypic characteristics. Six novel species, Haloarcula halophila sp. nov., Haloarcula litorea sp. nov., Haloarcula rara sp. nov., Haloarcula halobia sp. nov., Haloarcula pelagica sp. nov., and Haloarcula ordinaria sp. nov., are proposed to accommodate strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T, respectively.

Secofumitremorgins C and D, a pair of atropisomers from saltern-derived fungus Aspergillus fumigatus GXIMD00544.

A pair of atropisomers secofumitremorgins C (1a) and D (1b), together with fifteen known alkaloids (2-16), were isolated from a saltern-derived fungus Aspergillus fumigatus GXIMD00544. The structures of atropisomers 1a and 1b were elucidated by the detailed spectroscopic data, chemical reaction and quantum chemical calculations. Compounds 1 and 8 displayed antifungal spore germination effects against plant pathogenic fungus associated with sugarcane Fusarium sp. with inhibitory rates of 53% and 77% at the concentration of 100 µM, repectively. Atropisomers 1 also exhibited antifouling potential against Balanus amphitrite larval settlement with an inhibitory rate of 96% at the concentration of 100 µM.

Psychromarinibacter sediminicola sp. nov., a novel moderately halophilic, metabolically diverse bacterium isolated from a solar saltern sediment, and comparison between members of family Roseobacteraceae.

Known for its species abundance and evolutionary status complexity, family Roseobacteraceae is an important subject of many studies on the discovery, identification, taxonomic status, and ecological properties of marine bacteria. This study compared and analyzed the phylogenetic, genomic, biochemical, and chemo taxonomical properties of seven species from three genera (Psychromarinibacter, Lutimaribacter, and Maritimibacter) of the family Roseobacteraceae. Moreover, a novel strain, named C21-152T was isolated from solar saltern sediment in Weihai, China. The values of 16S rRNA gene sequence similarity, the average nucleotide identity (ANI), the average amino acid identity (AAI), and the digital DNA-DNA hybridization (dDDH) between genomes of the novel strain and Psychromarinibacter halotolerans MCCC 1K03203T were 97.19, 78.49, 73.45, and 21.90%, respectively. Genome sequencing of strain C21-152T revealed a complete Sox enzyme system related to thiosulfate oxidization as well as a complete pathway for the final conversion of hydroxyproline to α-ketoglutarate. In addition, strain C21-152T was resistant to many antibiotics and had the ability to survive below 13% salinity. This strain had versatile survival strategies in saline environments including salt-in, compatible solute production and compatible solute transport. Some of its physiological features enriched and complemented the knowledge of the characteristics of the genus Psychromarinibacter. Optimum growth of strain C21-152T occurred at 37 â„ƒ, with 5-6% (w/v) NaCl and at pH 7.5. According to the results of the phenotypic, chemotaxonomic characterization, phylogenetic properties and genome analysis, strain C21-152T should represent a novel specie of the genus Psychromarinibacter, for which the name Psychromarinibacter sediminicola sp. nov. is proposed. The type strain is C21-152T (= MCCC 1H00808T = KCTC 92746T = SDUM1063002T).

Gracilibacillus salinarum sp. nov. and Gracilibacillus caseinilyticus sp. nov., halotolerant bacteria isolated from a saltern environment.

Two aerobic, Gram-stain-positive, spore-forming motile bacterial strains, designated SSPM10-3T and SSWR10-1T, were isolated from salterns in Jeollanam province of South Korea. Both strains were halotolerant and grew well in 5 % NaCl but not in 20 and 25% NaCl, respectively. Optimal growth was observed with 5 % NaCl, at 30 °C and at pH 7.0-8.0. On the basis of the results of phylogenetic analysis using 16S rRNA gene sequence, both the strains were placed within the genus Gracilibacillus with Gracilibacillus massiliensis (98.65 % similarity) as their nearest neighbour. Menaquinone-7 (MK-7) (97 %) was the major isoprenoid quinone in both strains and major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 0. Orthologous average nucleotide identity with usearch (OrthoANIu) and digital DNA-DNA hybridisation (dDDH) percentage comparison indicated that SSPM10-3T and SSWR10-1T exhibited highest similarity with G. massiliensis Awa-1T at 74.27 % and 21.0 and 74.23 % and 20.0 %, respectively. The DNA G+C contents of the strains were 39.1 % (SSPM10-3T) and 38.5 % (SSWR10-1T). Members of the genus Gracilibacillus, both strains were distinct from each other with respect to their ability to produce urease, ß-glucosidase, assimilation of inulin and methyl-α-d-glucopyranoside and degradation of casein. Compared with each other, ANI and d4 dDDH calculations were only 88.2 % and 36.3 %, well below the cut-off values for species delineation for each index. On the basis of their phenotypic, physiological, biochemical and phylogenetic characteristics,SSPM10-3T and SSWR10-1T represent distinct novel species for which names Gracilibacillus salinarum SSPM10-3T and Gracilibacillus caseinilyticus SSWR10-1T are proposed. The type strains are SSPM10-3T (=KACC 21933T =NBRC 115502T) and SSWR10-1T (=KACC 21934T =NBRC 115503T).

Halobacillus salinarum sp. nov., Halobacillus shinanisalinarum sp. nov. and Halobacillus amylolyticus sp. nov., isolated from saltern soil.

Three bacterial strains, designated SSBR10-3T, SSTM10-2T and SSHM10-5T, were isolated from saltern soil sampled in Jeollanam-do, Republic of Korea. Cells were aerobic, Gram-stain-positive, flagellated and rod-shaped. The strains grew optimally at 28°C and at pH 7.0. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains SSBR10-3T, SSTM10-2T and SSHM10-5T were placed within the genus Halobacillus, showing the highest similarity to Halobacillus alkaliphilus FP5T (98.6 %), 'Halobacillus ihumii' Marseille-Q1234T (98.5 %) and Halobacillus locisalis MSS-155T (98.6 %), respectively. The genomic similarity values between strains SSBR10-3T, SSTM10-2T and SSHM10-5T and their related species were 17.6-22.6 % for digital DNA-DNA hybridization (dDDH) and 69.6-78.5 % for orthologous average nucleotide identity (OrthoANI), which were lower than the thresholds recommended for species delineation. The dDDH and OrthoANI values among the three strains were below 38.3 and 89.4 %, respectively. Besides the differences in genomic features, strains SSBR10-3T, SSTM10-2T and SSHM10-5T were distinct from each other and from members of the genus in terms of phenotypic traits related to substrate assimilation. The cell-wall peptidoglycan contained meso-diaminopimelic acid, the major fatty acids were anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0, and the predominant menaquinone was MK-7 for all three strains. Diphosphatidylglycerol, phosphatidylglycerol and an unidentified phospholipid were present in their polar lipid profiles. Based on a polyphasic approach incorporating genomic data, strains SSBR10-3T, SSTM10-2T and SSHM10-5T represent novel species, for which the names Halobacillus salinarum sp. nov. (SSBR10-3T=DSM 114353T=KACC 21935T=NBRC 115504T), Halobacillus shinanisalinarum sp. nov. (SSTM10-2T=DSM 114354T=KACC 21936T=NBRC 115505T) and Halobacillus amylolyticus sp. nov. (SSHM10-5T=DSM 114355T= KACC 21937T=NBRC 115506T) are proposed.

Streptomyces salinarius sp. nov., an actinomycete isolated from solar saltern soil.

An actinobacterium, designated strain SS06011T, was isolated from solar saltern soil collected from Samut Sakhon province, Thailand. The taxonomic position of this strain was established using the polyphasic taxonomic approach. The strain produced grey aerial spore mass on International Streptomyces Project 2 seawater agar that differentiated into spiral spore chains with rugose-surfaced spores. Strain SS06011T was found to have ll-diaminopimelic acid in the cell peptidoglycan. Whole-cell hydrolysates contained galactose, glucose and ribose. MK-9(H6) and MK-9(H4) were major menaquinones. The major cellular fatty acids comprised iso-C16 : 0, anteiso-C15 : 0 and anteiso-C17 : 0. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol were detected in cells. These characteristics were coincident with the typical morphological and chemotaxonomic properties of the genus Streptomyces. The taxonomic affiliation at the genus level of this strain could also be confirmed by its 16S rRNA gene sequence data. Strain SS06011T showed the highest 16S rRNA gene sequence similarity to Streptomyces ardesiacus NRRL B-1773T (99.1 %), Streptomyces coelicoflavus NBRC 15399T (99.1 %) and Streptomyces hyderabadensis OU-40T (99.1 %). Digital DNA-DNA hybridization (dDDH), average nucleotide identity-blast (ANIb) and average amino acid identity (AAI) values between strain SS06011T and its closely related type strains, S. ardesiacus NBRC 15402T, S. coelicoflavus NBRC 15399T and S. hyderabadensis JCM 17657T, were in the range of 45.4-48.4 % (for dDDH), 90.8-91.9 % (for ANIb) and 90.8-91.7 % (for AAI), respectively, which are lower than the cut-off criteria for species delineation. The DNA G+C content of genomic DNA was 71.9 mol%. With the differences in physiological, biochemical and genotypic data, strain SS06011T could be discriminated from its closest neighbours. Thus, strain SS06011T should be recognized as representing a novel species of the genus Streptomyces, for which the name Streptomyces salinarius sp. nov. is proposed. The type strain is SS06011T (=TBRC 9951T=NBRC 113998T).

Halobacterium wangiae sp. nov. and Halobacterium zhouii sp. nov., two extremely halophilic archaea isolated from sediment of a salt lake and saline soil of an inland saltern.

Two novel halophilic archaeal strains, Gai3-17T and XZYJT26T, were isolated from the sediment of Gaize salt lake and the saline soil of Mangkang ancient solar saltern in Tibet, PR China, respectively. Strains Gai3-17T and XZYJT26T were related to each other (96.5 and 89.7% similarity, respectively) and showed 97.5-95.4 and 91.5-87.7% similarities to the current members of Halobacterium based on 16S rRNA and rpoB' genes. The phylogenomic analysis indicated that strains Gai3-17T and XZYJT26T formed two distinct clades and clustered with the Halobacterium species. The two strains can be differentiated from the type strains of the six species with validly published names based on several phenotypic characteristics. The phospholipids of the two strains were phosphatidic acid, phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. One major glycolipid, sulphated galactosyl mannosyl glucosyl diether, was detected in strain Gai3-17T, while four glycolipids, mannosyl glucosyl diether, sulphated mannosyl glucosyl diether, disulphated mannosyl glucosyl diether and sulphated galactosyl mannosyl glucosyl diether were observed in strain XZYJT26T. The average nucleotide identity, digital DNA-DNA hybridization and amino acid identity values among the two strains and the members of Halobacterium were no more than 81, 25 and 77 %, respectively. These overall genome-related indices were below the threshold values for species boundary, indicating that strains Gai3-17T and XZYJT26T represent two novel species of Halobacterium. Thus, two novel species, Halobacterium wangiae sp. nov. and Halobacterium zhouii sp. nov., are proposed to accommodate strains Gai3-17T (=CGMCC 1.16101T=JCM 33551T) and XZYJT26T (=CGMCC 1.16682T=JCM 33556T), respectively.

Salinigranum marinum sp. nov. and Halohasta salina sp. nov., halophilic archaea isolated from sediment of a marine saltern and inland saline soil.

Two halophilic archaeal strains, ZS-10T and GSL13T, were isolated from the Zhoushan marine saltern in Zhejiang, and an inland saline soil from the Tarim Basin, Xinjiang, PR China, respectively. The cells of strain ZS-10T were pleomorphic while those of strain GSL13T were rod-shaped. Both of them stained Gram-negative and formed red-pigmented colonies on agar plates and their cells lysed in distilled water. The optimum growth of strain ZS-10T was observed at 40 °C, 3.4 M NaCl, 0.03 M MgCl2 and pH 7.5, while that of strain GSL13T was at 37 °C, 3.1 M NaCl, 0.5 M MgCl2 and pH 7.5. Phylogenetic and phylogenomic analyses indicated that these two strains were related to Salinigranum and Halohasta, respectively. Strains ZS-10T and GSL13T could be differentiated from the current members of Salinigranum and Halohasta based on the comparison of diverse phenotypic characteristics. The average amino acid identity, average nucleotide identity and digital DNA-DNA hybridization values among strain ZS-10T and current species of Salinigranum were 75.8-78.6 %, 80.6-81.9 % and 24.3-26.1 %, respectively. These values between strain GSL13T and current species of Halohasta were 78.4-80.8 %, 79.8-82.8% and 22.7-25.7 %, respectively, clearly below the threshold values for species demarcation. The polar lipids of strain ZS-10T were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me) and sulphated mannosyl glucosyl diether (S-DGD-1), while those of strain GSL13T were phosphatidic acid, PG, PGP-Me, phosphatidylglycerol sulphate and S-DGD-1. The polar lipid profile of strain GSL13T was identical to those of Halohasta, whereas strain ZS-10T did not contain the minor glycolipids detected in the current Salinigranum species. The phenotypic, phylogenetic and genome-based results suggested that strains ZS-10T (=CGMCC 1.12868T=JCM 30241T) and GSL13T (=CGMCC 1.15214T=JCM 30841T) represent two novel species, for which the names Salinigranum marinum sp. nov. and Halohasta salina sp. nov. are proposed.

Spontaneous granulation of moderately halophilic sludge inoculated with saltern sediments from single granule into multi-granule aggregation.

There is very limited research on the application of moderate halophiles for biotreatment of hypersaline wastewater widely generated from some industries. This study demonstrated the development of moderate halophiles inoculated from saltern sediments into aerobic granule sludge (AGS) to treat hypersaline wastewater with a salinity of 100 g/L. The granulation of moderate halophiles can occur without applying the settling velocity selective pressure. The saltern sediment initially aggregated into single small granules and finally developed into 1200 ± 50 µm multiparticle granules. The halophiles affiliated in Halomonas was dominant in the granular bacterial community, with a relative abundance of 94.52%. Halomonas ventosae secreted sulfated polysaccharides. The sulfated polysaccharides content accounted for 63.95 ± 2.10% in the polysaccharides (PS), having an adhesive role in connecting single granules. Multiparticle granules showed the clear stratified structure, with α-D-glucopyranose polysaccharides in the inner bounders and ß-D-glucopyranose polysaccharides in the outer. The moderately granular sludge showed the stable chemical oxygen demand (COD) removal efficiency of >90% and the aerobic total inorganic nitrogen (TIN) removal efficiency (equal to ammonia removal) of 70 ± 5.00%. This paper contributes new insight into the formation of moderately halophilic granular sludge and accelerates the application of moderately halophilic granular sludge to treat hypersaline wastewater.

Halorubrum salinarum sp. nov., an extremely halophilic archaeon isolated from a saturated brine pond of a saltern.

A novel extremely halophilic archaeon, strain RHB-CT, was isolated from a saturated brine pond of a solar saltern in Bolinao, Pangasinan, Philippines. Colonies were orange-red-pigmented, smooth, convex and round on a solid modified growth medium containing 25 % (w/v) of total salts. Cells of strain RHB-CT on the solid modified growth medium were ovoid-shaped (0.89-2.66 µm long), while the cells in a liquid modified growth medium were rod-shaped (1.53-5.65 µm long and 0.45-1.03 µm wide). The strain was Gram-stain-negative, motile and strictly aerobic. Strain RHB-CT grew with NaCl concentrations ranging from 10 to 30 % (w/v; optimum, 20-25 %), at pH 6.5-8.5 (optimum, pH 7.0-7.5) and at 20-55 °C (optimum, 40-45 °C). Furthermore, the strain grew even in the absence of Mg2+; however, when supplemented with Mg2+, growth was observed optimally at 0.2-0.4 M Mg2+. The 16S rRNA gene phylogeny inferred that the strain is a member of the genus Halorubrum and was related to Halorubrum xinjiangense CGMCC 1.3527T (99.0 %), Halorubrum sodomense DSM 3755T (98.8 %), Halorubrum coriense Ch2T (98.8 %), Halorubrum trapanicum NRC 34021T (98.4 %) and Halorubrum distributum JCM 9100T (98.1 %). The rpoB' gene sequences also showed that strain RHB-CT is related to Hrr. xinjiangense JCM 12388T (97.1 %), Hrr. distributum JCM 9100T (97.1 %), Hrr. coriense JCM 9275T (96.5 %), Hrr. californiense JCM 14715T (96.5 %), Hrr. trapanicum JCM 10477T (96.3%), Hrr. sodomense JCM 8880T (96.2%) and Hrr. tebenquichense DSM 14210T (95.6 %). The DNA G+C content of strain RHB-CT was 68.7 mol% (genome). Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain RHB-CT and the closely related species of Halorubrum were below 40 and 90 %, respectively, which are far below the thresholds to delineate a new species. The polar lipids of strain RHB-CT were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulphate and sulfated mannosyl glycosyl diether. Based on dDDH and ANI values, and the significant morphological and physiological differences from known taxa, it is hereby suggested that strain RHB-CT represents a novel species of the genus Halorubrum, for which the name Halorubrum salinarum sp. nov. is proposed. The type strain is RHB-CT (=KCTC 4274T=CMS 2103T).

Aquibacillus saliphilus sp. nov., a moderately halophilic bacterium isolated from a grey saltern.

A novel moderately halophilic bacterium, designated strain KHM2T, was isolated from the sediment of a grey solar saltern located on Sinui Island, Shinan, Republic of Korea. Cells were rod-shaped, endospore-forming, Gram-stain-positive, motile and facultative anaerobic. Strain KHM2T performed anaerobic respiration using nitrates and did not produce glucose acids, indicating the absence of fermentation. Strain KHM2T grew at 10-45 °C (optimum, 37 °C), pH 6.0-10.0 (optimum, pH 8.0) and with 1.0-20.0 % (w/v) NaCl (optimum, 10.0%). Based on 16S rRNA gene sequence similarity and chemotaxonomic properties, strain KHM2T was assigned to the genus Aquibacillus, with high 16S rRNA gene sequence similarity to Aquibacillus halophilus B6BT (98.2%) and less than 96.8 % similarity to the other recognized members of the genus Aquibacillus. The polar lipid profile consisted of diphosphatidylglycerol (DPG), phosphatidylglycerol (PG) and one unidentified phospholipid (PL). Major fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. The average nucleotide identity and digital DNA-DNA hybridization values of strain KHM2T with A. halophilus B6BT were 77.6 and 22.0 %, respectively. Based on the results of polyphasic analysis, strain KHM2T is proposed to represent a bacterial species within the genus Aquibacillus with the name Aquibacillus saliphilus sp. nov. The type strain is KHM2T (=KACC 19068T=NBRC 112577T).

Halorussus vallis sp. nov., Halorussus aquaticus sp. nov., Halorussus gelatinilyticus sp. nov., Halorussus limi sp. nov., Halorussus salilacus sp. nov., Halorussus salinisoli sp. nov.: six extremely halophilic archaea isolated from solar saltern, salt lake and saline soil.

Six novel halophilic archaeal strains of XZYJT10T, XZYJ18T, XZYJT40T, XZYJT49T, YCN54T and LT46T were isolated from a solar saltern in Tibet, a salt lake in Shanxi, and a saline soil in Xinjiang, China. Sequence similarities of 16S rRNA and rpoB' genes among strains XZYJT10T, XZYJ18T, XZYJT40T, XZYJT49T, YCN54T, LT46T and current members of Halorussus were 90.6-97.8% and 87.8-96.4%, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values among these six strains and current Halorussus members were in the range of 76.5-87.5% and 21.0-33.8%, respectively. These values were all below the species boundary threshold values. The phylogenomic tree based on 122 conserved archaeal protein marker genes revealed that the six novel strains formed individual distinct branches and clustered tightly with Halorussus members. Several phenotypic characteristics distinguished the six strains from current Halorussus members. Polar lipid analysis showed that the six novel strains contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and two to three glycolipids. Phenotypic, chemotaxonomic and phylogenetic properties showed that the six strains represented six novel species within the genus Halorussus, for which the names Halorussus vallis sp. nov., Halorussus aquaticus sp. nov., Halorussus gelatinilyticus sp. nov., Halorussus limi sp. nov., Halorussus salilacus sp. nov., and Halorussus salinisoli sp. nov. are proposed.

Genomic analysis of heavy metal-resistant Halobacterium salinarum isolated from Sfax solar saltern sediments.

The draft genome sequences of five archaeal strains, isolated from Sfax solar saltern sediments and affiliated with Halobacterium salinarum, were analyzed in order to reveal their adaptive strategies to live in hypersaline environments polluted with heavy metals. The genomes of the strains (named AS1, AS2, AS8, AS11, and AS19) are found to contain 2,060,688; 2,467,461; 2,236,624; 2,432,692; and 2,428,727 bp respectively, with a G + C content of 65.5, 66.0, 67.0, and 66.2%. The majority of these genes (43.69-55.65%) are annotated as hypothetical proteins. Growth under osmotic stress is possible by genes coding for potassium uptake, sodium efflux, and kinases, as well as stress proteins, DNA repair systems, and proteasomal components. These strains harbor many genes responsible for metal transport/resistance, such as: copper-translocating P-type ATPases, ABC transporter, and cobalt-zinc-cadmium resistance protein. In addition, detoxification enzymes and secondary metabolites are also identified. The results show strain AS1, as compared to the other strains, is more adapted to heavy metals and may be used in the bioremediation of multi-metal contaminated environments. This study highlights the presence of several commercially valuable bioproducts (carotenoids, retinal proteins, exopolysaccharide, stress proteins, squalene, and siderophores) and enzymes (protease, sulfatase, phosphatase, phosphoesterase, and chitinase) that can be used in many industrial applications.

The Diversity Patterns of Rare to Abundant Microbial Eukaryotes Across a Broad Range of Salinities in a Solar Saltern.

Solar salterns are excellent artificial systems for examining species diversity and succession along salinity gradients. Here, the eukaryotic community in surface water of a Korean solar saltern (30 to 380 practical salinity units) was investigated from April 2019 to October 2020 using Illumina sequencing targeting the V4 and V9 regions of 18S rDNA. A total of 926 operational taxonomic units (OTUs) and 1,999 OTUs were obtained with the V4 and V9 regions, respectively. Notably, most of the OTUs were microbial eukaryotes, and the high-abundance groups (> 5% relative abundance (RA), Alveolata, Stramenopila, Archaeplastida, and Opisthokonta) usually accounted for > 90% of the total cumulative read counts and > 80% of all OTUs. Moreover, the high-abundance Alveolata (larger forms) and Stramenopila (smaller forms) groups displayed a significant inverse relationship, probably due to predator-prey interactions. Most of the low-abundance (0.1-5% RA) and rare (< 0.1% RA) groups remained small portion during the field surveys. Taxonomic novelty (at < 90% sequence identity) was high in the Amoebozoa, Cryptista, Haptista, Rhizaria, and Stramenopila groups (69.8% of all novel OTUs), suggesting the presence of a large number of hidden species in hypersaline environments. Remarkably, the high-abundance groups had little overlap with the other groups, implying the weakness of rare-to-prevalent community dynamics. The low-abundance Discoba group alone temporarily became the high-abundance group, suggesting that it is an opportunistic group. Overall, the composition and diversity of the eukaryotic community in hypersaline environments may be persistently stabilized, despite diverse disturbance events.

Lentibacillus saliphilus. sp. nov., a moderately halophilic bacterium isolated from a saltern in Korea.

A novel moderately halophilic bacterial strain, designated YIM 93176T, was isolated from a saltern in Korea and subjected to a polyphasic taxonomic study. This isolate YIM 93176T was observed to grow in the presence of 0-22% (w/v) NaCl and at pH 6.0-10.0 and 10-45 °C; optimum growth was observed with 5-10% (w/v) NaCl and at pH 7.0-9.0 and 28-37 °C. Based on 16S rRNA gene sequences analysis, the nearest relatives were Lentibacillus alimentarius M2024T (96.5% similarity), followed by Virgibacillus carmonensis LMG 20964T (96.0%) and the other type strains of the family Bacillaceae, but phylogenetic analysis indicated that strain YIM 93176T belonged to the cluster comprising type species of the genus Lentibacillus. Genome sequencing of strain YIM 93176T revealed a genome size of 3.2 Mb and a DNA G + C content of 40.5 mol%. The major fatty acids were anteiso-C15:0 (40.7%) and iso-C15:0 (26.4%), while the predominant respiratory quinone was menaquinone 7. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. These genotypic and chemotaxonomic characteristics supported affiliation of strain YIM 93176T to the genus Lentibacillus. In addition, phenotypic characteristics could distinguish strain YIM 93176T from its closely related species in genus Lentibacillus. Based on the cumulative evidences from the polyphasic taxonomic study, strain YIM 93176T represents a novel species of the genus Lentibacillus, for which name Lentibacillus saliphilus sp. nov. (type strain YIM 93176T = CCTCC AB 208139T = DSM 21375T) is proposed.

Salt tolerance of halotolerant bacteria from coastal soils and sediments near saltern field of Hainan Island, China.

Understanding the salt tolerance of microbial communities may help to elucidate the effects of salt concentration and other environmental factors on soil biodiversity. Here, high-throughput sequencing of 16S rDNA and ITS was combined to investigate the distribution and salt tolerance of microbial communities in coastal soils and sediments near the Yinggehai saltern field of Hainan Island, China. The microbial communities in the soils and sediments of the land zone (YGHLS), the intertidal zone (YGHIS), and the inshore zone (YGHWS) were compared. PCoA of weighted and unweighted UniFrac distance revealed obvious differences in soil microbial community among different samples. ANOSIM analysis could clearly separate the three samples from each other. Three halotolerant bacteria, including Halomonas, Halobacillus and Wallemia, were found in the samples, which accounted for 0.0335 ± 0.0586%, 0.0241 ± 0.0304%, and 0.0308 ± 0.0445% of the total microbial community, respectively. The relative abundance of Trk system potassium uptake protein, Kdp operon response regulator, and Na+/H+ antiporter in the samples exceeded 0.09%, 0.06%, and 0.02%, respectively, indicating that the Trk system plays a major role in the salt tolerance of halotolerant bacteria in Yinggehai coastal soils and sediments.

Halobellus ruber sp. nov., a deep red-pigmented extremely halophilic archaeon isolated from a Korean solar saltern.

A novel halophilic archaeon, strain MBLA0160T, was isolated from a solar saltern in Sorae, Republic of Korea. The cells are deep-red pigmented, Gram-negative, rod shaped, motile, and lysed in distilled water. The strain MBLA0160T grew at 25-45 °C (optimum 37 °C), in 15-30% (w/v) NaCl (optimum 20%) and 0.1-1.0 M MgCl2 (optimum 0.3-0.5 M) at pH 5.0-9.0 (optimum 7.0). Phylogenetic analysis based on the 16S rRNA sequence showed that this strain was related to two species within the genus Halobellus (Hbs.), with 98.4% and 95.8% similarity to Hbs. salinus CSW2.24.4 T and Hbs. clavatus TNN18T, respectively. The major polar lipids of the strain MBLA160T were phosphatidylglycerol, phosphatidylglycerol sulfate, and phosphatidylglycerol phosphate methyl ester. The genome size, G + C content, and N50 value of MBLA0160T were 3.49 Mb, 66.5 mol%, and 620,127 bp, respectively. According to predicted functional proteins of strain MBLA0160T, the highest category was amino acid transport and metabolism. Genome rapid annotation showed that amino acid and derivatives was the most subsystem feature counts. Pan-genomic analysis showed that strain MBLA0160T had 97 annotated unique KEGG, which were mainly included metabolism and environmental information processing. Ortholog average nucleotide identities (OrthoANI) and in silico DNA-DNA hybridization (isDDH) values between the strain MBLA0160T and other strains of the genus Halobellus were under 84,4% and 28.1%, respectively. The genome of strain MBLA0160T also contain the biosynthetic gene cluster for C50 carotenoid as secondary metabolite. Based on the phylogenetic, phenotypic, chemotaxonomic properties, and comparative genomic analyses, strain MBLA0160T is considered to represent a novel species of the genus Halobellus, for which the name Halobellus ruber sp. nov. is proposed. The type strain is MBLA0160T (= KCTC 4291 T = JCM 34172 T).

Salinigranum halophilum sp. nov., isolated from marine solar salterns.

Three halophilic archaeal strains, YJ-53T, ZS-5 and DYF38, were isolated from marine solar salterns located in different provinces of China. The three strains formed a single cluster (99.7-99.8 and 97.9-99.2 % similarities, respectively) that was separate from the current two members of Salinigranum (96.7-98.0 and 89.8-92.9 % similarities, respectively) on the basis of 16S rRNA and rpoB' gene sequence comparisons and phylogenetic analysis. Diverse phenotypic characteristics differentiated strains YJ-53T, ZS-5 and DYF38 from Salinigranum rubrum GX10T and Salinigranum salinum YJ-50-S2T. The major polar lipids of isolated strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and two major glycolipids chromatographically identical to mannosyl glucosyl diether and sulfated mannosyl glucosyl diether, detected in the current members of Salinigranum. The OrthoANI and in silico DNA-DNA hybridization (DDH) values between the three strains were in the range of 97.7-98.4 % and 80.3-86.1 %, respectively, much higher than the threshold values proposed as species boundaries (average nucleotide identity 95-96 % and in silico DDH 70 %), revealing that the three strains represent one species. Results of comparative OrthoANI and in silico DDH analyses of the strains described in this study with validly described members of the genus Salinigranum supported that strains YJ-53T (=CGMCC 1.12860T=JCM 30238T), ZS-5 (=CGMCC 1.12867=JCM 30240) and DYF38 (=CGMCC 1.13779=JCM 33557) represent a novel species of the genus Salinigranum, for which the name Salinigranum halophilum sp. nov. is proposed.