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Microbial-assisted removal of natural or synthetic pollutants is the prevailing green, low-cost technology to treat polluted environments. However, the challenge with enzyme-assisted bioremediation is the laborious nature of dehalogenase-producing microorganisms’ bioprospecting. This bottleneck could be circumvented by in-silico analysis of certain microorganisms’ whole-genome sequences to predict their protein functions and enzyme versatility for improved biotechnological applications. Herein, this study performed structural analysis on a dehalogenase (DehHsAAD6) from the genome of Halomonas smyrnensis AAD6 by molecular docking and molecular dynamic (MD) simulations. Other bioinformatics tools were also employed to identify substrate preference (haloacids and haloacetates) of the DehHsAAD6. The DehHsAAD6 preferentially degraded haloacids and haloacetates (−3.2–4.8 kcal/mol) and which formed three hydrogen bonds with Tyr12, Lys46, and Asp182. MD simulations data revealed the higher stability of DehHsAAD6-haloacid- (RMSD 0.22–0.3 nm) and DehHsAAD6-haloacetates (RMSF 0.05–0.14 nm) complexes, with the DehHsAAD6-L-2CP complex being the most stable. The detail of molecular docking calculations ranked complexes with the lowest binding free energies as: DehHsAAD6-L-2CP complex (−4.8 kcal/mol) = DehHsAAD6-MCA (−4.8 kcal/mol) < DehHsAAD6-TCA (−4.5 kcal/mol) < DehHsAAD6-2,3-DCP (−4.1 kcal/mol) < DehHsAAD6-D-2CP (−3.9 kcal/mol) < DehHsAAD6-2,2-DCP (−3.5 kcal/mol) < DehHsAAD6-3CP (−3.2 kcal/mol). In a nutshell, the study findings offer valuable perceptions into the elucidation of possible reaction mechanisms of dehalogenases for extended substrate specificity and higher catalytic activity. Communicated by Ramaswamy H. Sarma

BACKGROUND Salinity is an essential abiotic stress in plants. Dunaliella is a genus of high-salt-tolerant microalgae. The present study aimed to compare the characterizations of D. bioculata and D. quartolecta at different levels and investigate novel genes response to salt stress. METHODS AND RESULTS High chlorophyll contents were detected in D. bioculata on the 35th d of salt stress, while high lipid and carotenoid contents were detected in D. quartolecta via morphological and biochemical analyses. Physiological analysis showed that D. quartolecta cells had a smaller increase in osmotic potential, a smaller decrease in the Na+/K+ ratio and photochemical efficiency (Fv/Fm), and a lower relative conductivity than D. bioculata cells. The genomic lengths of D. quartolecta and D. bioculata were 396,013,629 bp (scaffold N50 = 1954 bp) and 427,667,563 bp (scaffold N50 = 3093 bp) via high-throughput sequencing and de novo assembly, respectively. Altogether, 25,751 and 26,620 genes were predicted in their genomes by annotation analysis with various biodatabases. The D. bioculata genome showed more segmental duplication events via collinearity analysis. More single nucleotide polymorphisms and insertion-deletion variants were detected in the D. bioculata genome. Both algae, which showed a close phylogenetic relationship, may undergo positive selection via bioinformatics analysis. A total of 382 and 85 novel genes were screened in D. bioculata and D. quartolecta, with 138 and 51 enriched KEGG pathways, respectively. Unlike the novel genes adh1, hprA and serA, the relative expression of livF and phbB in D. bioculata was markedly downregulated as salinity increased, as determined by qPCR analysis. The relative expression of leuB, asd, pstC and proA in D. quartolecta was markedly upregulated with the same salinity increase. CONCLUSION Dunaliella quartolecta is more halophilic than D. bioculata, with more effective responses to high salt stress based on the multiphase comparative data.

Halorhodospira halophila, one of the most-xerophilic halophiles, inhabits biophysically stressful and energetically expensive, salt-saturated alkaline brines. Here, we report an additional stress factor that is biotic: a diminutive Candidate-Phyla-Radiation bacterium, that we named ‘Ca. Absconditicoccus praedator’ M39-6, which predates H. halophila M39-5, an obligately photosynthetic, anaerobic purple-sulfur bacterium. We cultivated this association (isolated from the hypersaline alkaline Lake Hotontyn Nur, Mongolia) and characterized their biology. ‘Ca. Absconditicoccus praedator’ is the first stably cultivated species from the candidate class-level lineage Gracilibacteria (order-level lineage Absconditabacterales). Its closed-and-curated genome lacks genes for the glycolytic, pentose phosphate- and Entner–Doudoroff pathways which would generate energy/reducing equivalents and produce central carbon currencies. Therefore, ‘Ca. Absconditicoccus praedator’ is dependent on host-derived building blocks for nucleic acid-, protein-, and peptidoglycan synthesis. It shares traits with (the uncultured) ‘Ca. Vampirococcus lugosii’, which is also of the Gracilibacteria lineage. These are obligate parasitic lifestyle, feeding on photosynthetic anoxygenic Gammaproteobacteria, and absorption of host cytoplasm. Commonalities in their genomic composition and structure suggest that the entire Absconditabacterales lineage consists of predatory species which act to cull the populations of their respective host bacteria. Cultivation of vampire : host associations can shed light on unresolved aspects of their metabolism and ecosystem dynamics at life-limiting extremes.

Three novel halophilic archaea were isolated from seawater and sediment near Yeoungheungdo Island, Republic of Korea. The genome size and G + C content of the isolates MBLA0076T, MBLA0077T, and MBLA0078T were 3.56, 3.48, and 3.48 Mb and 61.7, 60.8, and 61.1 mol%, respectively. The three strains shared 98.5–99.5 % sequence similarity of the 16 S rRNA gene, whereas their sequence similarity to the 16 S rRNA gene of type strains was below 98.5 %. Phylogenetic analysis based on sequences of the 16 S rRNA and RNA polymerase subunit beta genes indicated that the isolates belonged to the genus Haloferax. The orthologous average nucleotide identity, average amino-acid identity, and in silico DNA-DNA hybridization values were below species delineation thresholds. Pan-genomic analysis indicated that the three novel strains and 11 reference strains had 8981 pan-orthologous groups in total. Fourteen Haloferax strains shared 1766 core pan-genome orthologous groups, which were mainly related to amino acid transport and metabolism. Cells of the three isolates were gram-negative, motile, red-pink pigmented, and pleomorphic. The strains grew optimally at 30 °C (MBLA0076T) and 40 °C (MBLA0077T, MBLA0078T) in the presence of 1.28 M (MBLA0077T) and 1.7 M (MBLA0076T, MBLA0078T) NaCl and 0.1 M (MBLA0077T), 0.2 M (MBLA0076T), and 0.3 M (MBLA0078T) MgCl2·6H2O at pH 7.0–8.0. Cells of all isolates lysed in distilled water; the minimum NaCl concentration necessary to prevent lysis was 0.43 M. The major polar lipids of the three strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, and sulphated diglycosyl archaeol-1. Based on their phenotypic and genotypic properties, MBLA0076T, MBLA0077T, and MBLA0078T were described as novel species of Haloferax, for which we propose the names Haloferax litoreum sp. nov., Haloferax marinisediminis sp. nov., and Haloferax marinum sp. nov., respectively. The respective type strains of these species are MBLA0076T (= KCTC 4288T = JCM 34,169T), MBLA0077T (= KCTC 4289T = JCM 34,170T), and MBLA0078T (= KCTC 4290T = JCM 34,171T).

Several archaea harbour genes that code for fructosyltransferase (FTF) enzymes. These enzymes have not been characterized yet at structure-function level, but are of extreme interest in view of their potential role in the synthesis of novel compounds for food, nutrition and pharmaceutical applications. In this study, 3D structure of an inulin-type fructan producing enzyme, inulosucrase (InuHj), from the archaeon Halalkalicoccus jeotgali was resolved in its apo form as well as with bound substrate (sucrose) molecule and first transglycosylation product (1-kestose). This is the first crystal structure of an FTF from halophilic archaea. Its overall five-bladed β-propeller fold is conserved with previously reported FTFs, but also shows some unique features. The InuHj structure is closer to those of Gram-negative bacteria, with exceptions such as residue E266, which is conserved in FTFs of Gram-positive bacteria and has possible role in fructan polymer synthesis in these bacteria as compared to fructooligosaccharide (FOS) production by FTFs of Gram-negative bacteria. Highly negative electrostatic surface potential of InuHj, due to a large amount of acidic residues, likely contributes to its halophilicity. The complex of InuHj with 1-kestose indicates that the residues D287 in the 4B-4C loop, Y330 in 4D-5A and D361 in the unique α2 helix may interact with longer FOSs and facilitate the binding of longer FOS chains during synthesis. The outcome of this work will provide targets for future structure-function studies of FTF enzymes, particularly those from archaea.

Extremophiles are organisms that can thrive under extreme environmental conditions. There are many types of extremophiles, which require different growth conditions and habitats to grow; among them are the halophilic and the halotolerant microbes. These microbes are reported to grow in habitats of high salinity regions including the sea, sediments, lakes, mines, plant and the soil. They need high carbon source and salt concentration to achieve maximum tolerable condition for their survival. High salinity survival and tolerance of these microbes are mechanized due to their osmotic and ionic stress, which are regulated through their genetic expression of enzymes, proteins, cell wall compositions and transporters. Thus, due to their robustness; the halophiles and halotolerant fungi showed high potential in health care; antimicrobial and anticancer activity, nanoparticle synthesis, enzyme production, genetics, bioremediation and other aspects. The aim of the current study was to explore the halophilic and halotolerant fungi, which are least explored for their habitats, growth requirements, and mechanism for salt resistance and tolerance. This will be followed by their biotechnological applications focusing on the biomedical industry, due to the emergence of the new multi-drug resistant pathogenic microbes.

Two strains of the halophilic alga Dunaliella parva, a wild type (WT) and a transgenic strain (D-PSY) containing an exogenous phytoene synthase gene (PSY), were used to investigate the growth, carotenoid accumulation, and carotenoid antioxidant properties under nitrogen starvation, cobalt and biochar treatments. D-PSY had higher carotenoid content (1.8 times) compared to the WT. The applied stressors stimulated the carotenoid content of both WT and D-PSY especially. The carotenoids were assayed for the potential antioxidant activities by five different assays. Generally, the antioxidant activities of D-PSY carotenoids were superior to that of WT. The biochar and nitrogen treatments generally enhanced the antioxidant activities of the carotenoids, whereas cobalt came third in this respect. The D-PSY transgenic algal strain has both high carotenoids content and antioxidant properties which enhanced under the relatively lower concentrations of the applied stressors. The results have shown to lead to an accurate application of the transgenic alga as a source of potent antioxidant compounds. Supplementary information The online version contains supplementary material available at 10.1007/s12298-021-01077-0.

A moderately halophilic bacterium isolated from the water samples collected from a salt field, Salinivibrio sp. TGB10 was found capable of producing poly-3-hydroxybutytate (PHB) from various sugars. Cell dry weight (CDW) of 8.82 g/L and PHB titer of 6.84 g/L were obtained using glucose as the carbon source after 24 h of cultivation in shake flasks. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was synthesized when propionate was provided as secondary carbon source. Salinivibrio sp. TGB10 exhibited favorable tolerance to propionate. The use of 8 g/L propionate and 20 g/L glucose as combinational substrates yielded 1.45 g/L PHBV with a 3-hydroxyvalerate monomer content of 72.02 mol% in flask cultures. In bioreactor study, CDW of 33.45 g/L and PHBV titer of 27.36 g/L were obtained after 108 h of fed-batch cultivation. The results indicated that Salinivibrio sp. TGB10 is a promising halophilic bacterium for the production of PHBV with various polymer compositions.

This study aimed at the amylase production using seawater instead of fresh water. Amylase is one of the most important enzymes and is very important for biotechnology. Versatile applications of amylase in many industries make optimization of the manufacturing process to achieve maximum yield is in need. Amylase is a widely used and sought-after industrial enzyme. The current research paper describes the production conditions of extracellular amylase from Oscillatoria acutissima. The marine cyanobacterium Oscillatoria acutissima culture was statistically optimized using Plackett-Burman and Box-Behnken designs, under submerged fermentation conditions, for optimum amylase production and activity conditions. The verified Plackett-Burman and Box-Behnken designs results showed that the starch degradation and incubation period improved significantly from 53% to 99% and from 18th to 12th days incubation period, respectively, with pH = 7 at temperature 35°C. SDS-PAGE resolved the molecular weight of partially purified amylase at 72 kilodalton. This research work suggested that marine cyanobacterium Oscillatoria acutissima could be a potential source of halophilic amylase enzyme needed for various industrial processes. To the best of our knowledge, this is one of a few studies on cyanobacteria since while and the first report on amylase production by marine cyanobacterium Oscillatoria acutissima.

In the current study, fourteen bacterial strains were obtained in salt contaminated soils. The identification and characterization of the bacterial strains were performed by conventional and molecular techniques. According to the results of 16S rRNA gene sequence analysis, five genera (Bacillus, Staphylococcus, Oceanobacillus, Exiguobacterium, and Halobacillus) were identified with a homology of equal to 99% or higher similarity. Afterward, these fourteen halotolerant/halophilic bacterial strains were investigated for their plant growth promoting (PGP) traits including production of indole-3-acetic acid (IAA) and siderophore, activity of 1-aminocyclopropane-1-carboxylate (ACC) deaminase, fixation of nitrogen, and phosphate solubilization potential. Five of the bacterial strains possessing PGP traits were tested for their effects on the growth of a salt sensitive plant (wheat) in a hydroponic system under salt stress (200 mM). Inoculation of five bacterial strains under salt stress significantly enhanced plant weight (Triticum aestivum) ranged from 71.18 to 89.04%. Salt stress amelioration potential of Oceanobacillus picturae and Staphylococcus succinus on T. aestivum has been shown for the first time in this study. In non-saline soil, the promising effect of plant growth bacteria is clear; however, in saline soil, the use of PGP halophilic and halotolerant bacteria can increase the productivity of salt sensitive plants. Therefore, the novel halophilic and halotolerant bacteria that promote plant growth can be developed for agricultural uses in saline soils., Agri Ibrahim Cecen University Scientific Researches Project [BAP-F.E.F.18.005], This study was supported by Agri Ibrahim Cecen University Scientific Researches Project (Project number: BAP-F.E.F.18.005).

A novel moderately thermophilic and halophilic bacterium, designated strain M0105T, was isolated from mangrove sediment collected in the Beibu Gulf, south China. The isolate is Gram-negative, non-motile and rod-shaped bacterium with smooth colonies of pale-yellow appearance. Growth occurs at 15–46 °C (optimum 37–40 °C) and pH range of 6.0–10.0 (optimum pH 8.0–9.0). It required 1–7% NaCl (optimum 3–5%) for growth. Strain M0105T was affiliated to the family ‘Rhodobacteraceae’, sharing the highest 16S rRNA gene sequence similarity with Limibaculum halophilum CAU 1123T (96.8%). The major menaquinone Q-10 and the dominant unsaturated fatty acid (C18:1ω7) in this family were also detected in the strain M0105T. The genome sequence possesses a circular 4.1 Mb chromosome with a G + C content of 67.9%. Strain M0105T encoded many genes for cellular stress resistance and nutrient utilization, which could improve its adaptive capacity to the mangrove environment. Values of conserved proteins (POCP), average nucleotide identity, average amino acid identity (AAI) and DNA–DNA hybridization (dDDH) between the isolate and closely related species were below the proposed threshold for species discrimination. Information from phenotypic, chemotaxonomic and phylogenetic analyses proposed that strain M0105T should be assigned to a novel genus within the family ‘Rhodobacteraceae’. Thus, we suggested that the strain M0105T represents a novel species in a new genus, for which the name Thermohalobaculum xanthum gen. nov., sp. nov. is proposed. The type strain of the type species is M0105T (= BGMRC 2019T = KCTC 52118T = MCCC 1K03767T = NBRC 112057T).

Salt stress is an abiotic stress to plants in especially saline lakes. Dunaliella, a halophilic microalga distributed throughout salt lakes and seas, can respond to different salinity stresses by regulating the expression of some genes. However, these genes and their function and biological processes involved remain unclear. Profiling these salt-stress-related genes in a high-salt-tolerant Dunaliella species will help clarify the salt tolerance machinery of Dunaliella. Three D. salina_YC salt-stress groups were tested under low (0.51 mol/L), moderate (1.03 mol/L), and high (3.42 mol/L) NaCl concentrations and one control group under very low (0.05 mol/L) NaCl concentration and 3 transcriptome results that were deep sequenced and de novo assembled were obtained per group. Twelve high-quality RNA-seq libraries with 46 585 upregulated and 47 805 downregulated unigenes were found. Relative to the control, 188 common differentially expressed genes (DEGs) were screened and divided into four clusters in expression pattern. Fifteen of them annotated in the significant enriched Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were validated via qPCR. Their qPCR-based relative expression patterns were similar to their RNA-seq-based patterns. Two significant DEGs, the geranylgeranyl diphosphate synthase coding gene (1 876 bp cDNA) and diacylglycerol O-acyltransferase coding gene (2 968 bp cDNA), were cloned and analyzed in silico. The total lipid content, superoxide dismutase specific activity, and beta, carotene content of D. salina_YC increased gradually with increasing salinity. In addition, the expression of 11 validated genes involved in fatty acid biosynthesis/degradation, active oxygen or carotenoid metabolisms showed significant changes. In addition, algal photochemical efficiency was diminished with increasing salinity, as well as the expression of 4 photosynthesis-related genes. These results could help clarify the molecular mechanisms underlying D. salina responses to the Yuncheng Salt Lake environment and lay a foundation for further utilization of this algal resource.

Hypersaline environment is a habitat with extreme osmotic conditions along with low Aw, serving as a home to extremely halophilic and halotolerant bacteria. The hypersaline environments, such as so...

Higher plants and microorganisms produce uricase that oxidizes uric acid to allantoin. The lack of uricase in higher primates and humans causes uric acid accumulation. Today, the uricase treatment of hyperuricemia has been considered as a remedy. Uricases vary slightly in their origins and structures. Halophilic bacteria synthesize uricase with acidic amino acids at the surface. Fifty-eight halophilic strains isolated from Iranian saline lakes were screened for uricase production. The bacteria were cultured on a medium containing 5% salt and 0.3% uric acid and were assayed at 293 nm. The cultures were optimized by analyzing the effect of physical and chemical factors on the bacterial biomass and uricase production. Out of 18 strains, those were positive for uric-lytic activity, Halobacillus sp. strain GCFx14 with the highest uricase activity at (0.131 U/ml) showed the closest relationship to Halobacillus trueperi (99.00%), and Halobacillus profundi and Halobacillus faecis (98.87%), respectively. The optimum temperature for uricase activity (0.261 U/ml) was 40 °C. The mass of Halobacillus sp. strain GCFx14 produced uricase with the activity of 0.233 U/ml at pH 9, while 1% salinity led to 0.215 U/ml activity of uricase. pH of 8.0, temperature of 35 $$^\circ $$ C, salinity of 2.5%, and 0.2% uric acid were the optimum conditions to produce the highest amount of uricase in Halobacillus sp. strain GCFx14. The highest induction of uricase production in the strain was obtained using yeast extract and peptone (meat) as nitrogen and carbon sources.

In this study, fluorescence in situ hybridization (FISH) and PCR-amplified fragments of the 16SrDNA gene were used to determine prokaryotes diversity in Urmia Salt Lake. Prokaryote cell population in Urmia lake range from 3.1 ± 0.3 × 106, 2 ± 0.2 × 108, 4 ± 0.3 × 108, and 1.8 ± 0.2 × 108 cells ml−1 for water, soil, sediment, and salt samples by DAPI (4, 6-diamidino-2-phenylindole) direct count, respectively. The proportion of bacteria and archaea in the samples determinable by FISH ranged between 36.1 and 55% and 48.5 and 55.5%, respectively. According to the DGGE method, some bands were selected and separated from the gel, then amplified and sequenced. The results of sequences were related to two phyla Proteobacteria (16.6%) and Bacteroidetes (83.3%), which belonged to four genera Salinibacter, Mangroviflexus, Pseudomonas, and Cesiribacter, and the archaeal sequences were related to Euryarchaeota phyla and three genera Halonotius, Haloquadratum, and Halorubrum. According to our results, it seems that prokaryotic populations in this hypersaline environment are more diverse than expected, and bacteria are so abundant and diverse and form the metabolically active part of the microbial population inhabiting this extreme environment. Molecular dependent and independent approaches revealed a different aspect of this environment microbiota.

This study synthesises information on the biology of the unique and diverse halophilic macroinvertebrates of Australian salt lakes, focusing on gastropods and crustaceans. This information is needed to evaluate and manage the threats posed to these invertebrates by increased periods of drought and secondary salinisation. Most of these species are endemic to Australian salt lakes, and some have adapted to extreme conditions (e.g. salinities >100 g L–1 and pH

We previously demonstrated the production and purification of novel halo-acid-alkali-thermo-stable xylanase from halophilic bacterium Gracilibacillus sp. TSCPVG using submerged fermentation (SmF). In this work, we further showed the production of halophilic xylanase by solid state fermentation (SSF) from halophilic bacterium Gracilibacillus sp. TSCPVG using cheap solid-substrate wheat bran. High levels of enzyme titers (657 U/g dw) were obtained after varying certain SSF parameters such as incubation period, particle size, moisture ratio, salinity, pH, temperature and by supplementing different carbon and nitrogen sources externally to the fermentation medium. This bacterium could be a novel strain due to its ability to produce high titers of xylanase with extremophilic characters even under the conditions of SSF. Thus, this beneficiary role may lead to a substantial reduction in the overall cost of enzyme production and may have a huge impact on the economics of hemicellulose degradation under high saline conditions.

Aerosols play a crucial role in cloud formation. Biologically derived materials from bacteria, fungi, pollen, lichen, viruses, algae, and diatoms can serve as ice nucleating particles (INPs), some of which initiate glaciation in clouds at relatively warm freezing temperatures. However, determining the magnitude of the interactions between clouds and biologically derived INPs remains a significant challenge due to the diversity and complexity of bioaerosols and limited observations of such aerosols facilitating cloud ice formation. Additionally, microorganisms from the domain Archaea have, to date, not been evaluated as INPs. Here, we present the first results reporting the ice nucleation activity of four species in the class Haloarchaea. Intact cells of Halococcus morrhuae and Haloferax sulfurifontis demonstrated the ability to induce immersion freezing at temperatures up to −18 ∘C, while lysed cells of Haloquadratum walsbyi and Natronomonas pharaonis were unable to serve as immersion INPs. Exposure to heat and peroxide digestion indicated that the INPs of intact cells were driven by organic (H. morrhuae and H. sulfurifontis) and possibly also heat labile materials (H. sulfurifontis only). While halophiles are prominent in hypersaline environments such as the Great Salt Lake and the Dead Sea, other members of the Archaea, such as methanogens and thermophiles, are prevalent in anoxic systems in seawater, sea ice, marine sediments, glacial ice, permafrost, and other cold niches. Archaeal extremophiles are both diverse and highly abundant. Thus, it is important to assess their ability to serve as INPs as it may lead to an improved understanding of biological impacts on clouds.

Total synthesis of the pentasaccharide repeating unit of the OPS from Halomonas ventosae RU5S2EL is accomplished through a [3+2] block strategy. Picoloyl-induced hydrogen-bond-assisted aglycon delivery (HAD) is used for two consecutive 1,2-cis-l-rhamnosylations, and remote participation is used for α-selective glucosylation. The choice of 2-aminoethyl glycoside at the reducing end is opted for, leaving the scope for further glycoconjugate formation without hampering the reducing-end stereochemistry.

Background Lentibacillus species are gram variable aerobic bacteria that live primarily in halophilic environments. Previous reports have shown that bacteria belonging to this species are primarily isolated from salty environments or food. We isolated a bacterial strain CBA3610, identified as a novel species of the genus Lentibacillus, from a human fecal sample. In this report, the whole genome sequence of Lentibacillus sp. CBA3610 is presented, and genomic analyses are performed. Results Complete genome sequence of strain CBA3610 was obtained through PacBio RSII and Illumina HiSeq platforms. The size of genome is 4,035,571 bp and genes estimated to be 4714 coding DNA sequences and 64 tRNA and 17 rRNA were identified. The phylogenetic analysis confirmed that it belongs to the genus Lentibacillus. In addition, there were genes related to antibiotic resistance and virulence, and genes predicted as CRISPR and prophage were also identified. Genes related to osmotic stress were found according to the characteristics of halophilic bacterium. Genomic differences from other Lentibacillus species were also confirmed through comparative genomic analysis. Conclusions Strain CBA3610 is predicted to be a novel candidate species of Lentibacillus through phylogenetic analysis and comparative genomic analysis with other species in the same genus. This strain has antibiotic resistance gene and pathogenic genes. In future, the information derived from the results of several genomic analyses of this strain is thought to be helpful in identifying the relationship between halophilic bacteria and human gut microbiota.

Increasing environmental pollutants such as heavy metals have become one of the most severe health dangers because of rapid industrialization. Exposure to lead and nickel heavy toxic metals can lead to hazardous diseases affecting most of the organs in humans. Bioremediation is a process that uses the ability of microorganisms or plants to detoxify environmental contaminants at lower costs than physicochemical techniques. This study isolated halophilic bacteria from Khara salt lake in Iran and screened their ability to resist lead and nickel. After screening stages, three selected strains including Bacillus sp. A21, Oceanobacillus sp. A22 and Salinicoccus A43 were identified by16S rDNA sequencing and the related sequences were submitted to GeneBank with accession IDs MN588312, MN588313, and MN 588,314, respectively. These strains resist 7.2 mM, 4.1 mM, and 6.7 mM lead and 3.6 mM, 3.7 mM, and 4.1 mM nickel, respectively. Investigation of growth pattern and evaluation of bioremediation ability by atomic absorption spectroscopy revealed that Bacillus sp. A21 could decrease lead and nickel in culture medium up to 97.5% and 76%, respectively. Oceanobacillus sp. A22 showed higher lead bioremediation rate (98.8%) and lower nickel-bioremediation rate (73.5%). Salinicoccus sp. A43 showed the least bioremediation ability (92% lead and 71.7% nickel). The ability of selected strains to synthesize lead and nickel nanoparticles was evaluated using UV/Vis spectrophotometry and Energy-Dispersive X-ray Spectroscopy (EDX). Particle dimensions were measured using Scanning Electron Microscopy (SEM). Bacillus sp. A21 and Oceanobacillus sp. A22 strains were able to synthesize lead nanoparticles; however, Salinicoccus sp. A43 could synthesize both lead and nickel nanoparticles.

Large regions of Earth's surface are underlain by salt deposits that evaporated from ancient oceans and are populated by extreme halophilic microbes. Some of these halophiles may have been preserved over geological timescales within hypersaline fluid inclusions, but ingresses of water and/or anthropogenic activities can lead to the formation of alternative habitats, including NaCl stalactites or speleothems. While the microbiology of ancient evaporites has been well-studied, the ecology of these recently formed structures is less-well understood. Here, the microbiology of a NaCl stalactite ('salticle') in a Triassic halite mine is characterised. The specific aims were to: determine the presence of fluid inclusions; determine the microbial structure of the salticle compared with a nearby brine-pool and surficial soil; and characterise the ecophysiological capabilities of this unique ecosystem. The salticle contained fluid inclusions, and their microbiome was composed of Euryarchaetota, Proteobacteria, and Actinobacteria, with Haloarchaea in greater abundance than brine-pool or soil microbiomes. The salticle metagenome exhibited a greater abundance of genes involved in osmoregulation, anaerobic respiration, UV resistance, oxidative stress, and stress-protein synthesis relative to the soil microbiome. We discuss the potential astrobiological implications of salticles as enclosed salt-saturated habitats that are protected from ionising radiation and have a stable water-activity. This article is protected by copyright. All rights reserved.

Objective: Microorganisms play an important role in all ecosystem processes and a growing body of molecular and ecological evidence has shown that microbial biodiversity is much more diverse and complex than previously anticipated. This study aimed to determine the prokaryotic microorganisms present in Gokceada Salt Lake Lagoon. Materials and Methods: A metabarcoding approach was used to determine the microbial diversity in Gokceada Salt Lake Lagoon. Results: 16S rDNA targeted sequencing revealed 5 Archaea and 31 Bacteria species and Archaea represented 63.2%. The most frequent Archaea genus was Halorubrum, which belongs to the Euryarchaeota phylum, and the dominant species of Bacteria was Halomonas sulfidaeris (Proteobacteria phylum). Conclusion: This work will contribute to our understanding of the microbial community structure and composition in coastal lagoons. Hovewer, further surveys will improve our knowledge on microbiota in Gokceada Salt Lake Lagoon.

To date, all species in the genus Salicibibacter have been isolated in Korean commercial kimchi. We aimed to describe the taxonomic characteristics of two strains, NKC5-3T and NKC21-4T, isolated from commercial kimchi collected from various regions in the Republic of Korea. Cells of these strains were rod-shaped, Gram-positive, aerobic, oxidase- and catalase-positive, non-motile, halophilic, and alkalitolerant. Both strains, unlike other species of the genus Salicibibacter, could not grow without NaCl. Strains NKC5-3T and NKC21-4T could tolerate up to 25.0% (w/v) NaCl (optimum 10%) and grow at pH 7.0-10.0 (optimum 8.5) and 8.0-9.0 (optimum 8.5), respectively; they showed 97.1% 16S rRNA gene sequence similarity to each other and were most closely related to S. kimchii NKC1-1T (97.0% and 96.8% similarity, respectively). The genome of strain NKC5-3T was nearly 4.6 Mb in size, with 4,456 protein-coding sequences (CDSs), whereas NKC21-4T genome was nearly 3.9 Mb in size, with 3,717 CDSs. OrthoANI values between the novel strains and S. kimchii NKC1-1T were far lower than the species demarcation threshold. NKC5-3T and NKC21-4T clustered together to form branches that were distinct from the other Salicibibacter species. The major fatty acids in these strains were anteiso-C15:0 and anteiso-C17:0, and the predominant menaquinone was menaquinone-7. The polar lipids of NKC5-3T included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), and five unidentified phospholipids (PL), and those of NKC21-4T included DPG, PG, seven unidentified PLs, and an unidentified lipid. Both isolates had DPG, which is the first case in the genus Salicibibacter. The genomic G + C content of strains NKC5-3T and NKC21-4T was 44.7 and 44.9 mol%, respectively. Based on phenotypic, genomic, phylogenetic, and chemotaxonomic analyses, strains NKC5-3T (= KACC 22040T = DSM 111417T) and NKC21-4T (= KACC 22041T = DSM 111418T) represent two novel species of the genus Salicibibacter, for which the names Salicibibacter cibarius sp. nov. and Salicibibacter cibi sp. nov. are proposed.

A Gram-stain-negative, long-rod shaped, and facultatively anaerobic bacterium, designated as strain M1T, was isolated from the marine sediment of Jeju Island, South Korea. Strain M1T was found to be catalase- and oxidase-positive, light yellow-pigmented, non-motile, and non-flagellated, growing optimally at 30 °C, pH 7.0, and in the presence of 3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain M1T belongs to the genus Draconibacterium and is closely related to Draconibacterium orientale FH5T (97.2%), Draconibacterium sediminis JN14CK-3 T (96.5%), “Draconibacterium filum” F2T (96.5%) and Draconibacterium mangrovi GM2-18 T (96.3% sequence similarity). The values for digital DNA-DNA hybridization ranged from 37.6 to 38.3% against D. orientale FH5T, D. sediminis KN14CK-3 T, and D. mangrovi GM2-18 T, clearly indicating that strain M1T represents a distinct species of the genus Draconibacterium. Strain M1T has a 40.0% G + C content estimated by genome sequence, menaquinone 7 as the sole respiratory quinone, C15:0 anteiso and C15:0 iso as the major fatty acids, and phosphatidylethanolamine, an unidentified phospholipid, and unidentified lipids as the polar lipids. Based on the polyphasic characteristics, it is suggested that strain M1T be assigned to the genus Draconibacterium as the type strain of a novel species, for which the name Draconibacterium halophilum sp. nov. is proposed. The type strain is M1T (= KCTC 72809 T = VTCC 910107 T).

Introduction. The material shows halophiles bacteria R. Psendomonas the water’s microbiota and the pikeperch in spring and autumn. The attachment of Pseudomonas isolated from these habitats, certain Delta areas has not been identified. Materials and methods. 190 “water” strains and 720 ones isolated from fish were experimentally tested. In meat-peptone broth (MPB) with 3.0, 7.0, and 10.0% NaCl content, daily cultures of analyzed bacteria were sown, incubation of which was carried out at 37 °C, and the results were taken into account after 24 and 48 hours. Results. There were no significant differences in halophilicity in the analyzed strains, except for the autumn season, especially in 10.0% salt solution. Among the isolated pseudomonads, the maximum halotolerance in both biotopes was observed in P. fluorescens and P. alcaligenes in P. putida. Halophiles strains of Pseudomonas that infect the water and fish had seasonal cycles. A slight decrease in the halophilicity of pseudomonades persistent in water and fish only at concentrations of 3.0 and 10.0 mg/l from spring to summer (1.1-1.2 times), and their significant rise in autumn (1.5 and 1.4 times) in the salt concentration of 3.0 mg/l. In the tested strains in spring and autumn, increased salt tolerance values were noted, which was determined by the hydrological and hydrochemical features of Delta waters and the “transfer” of bacteria in the body of walleye during its migration from the sea to the river. Conclusion. Analysis of long-term material showed high halophiles studied strains of pseudomonad, indicating that their sanitary and epidemiologic danger, and the ability to remain viable in salted fish products

A halophilic, Gram-staining-negative, rod-shaped, flagellated and motile bacterium, strain QX-1 T, was isolated from deep-sea sediment at a depth of 3332 m in the southwestern Indian Ocean. Strain QX-1 T growth was observed at 4–50 °C (optimum 37 °C), pH 5.0–11.0 (optimum pH 7.0), 3–25% NaCl (w/v; optimum 7%), and it did not grow without NaCl. A phylogenetic analysis based on the 16S rRNA gene placed strain QX-1 T in the genus Halomonas and most closely related to Halomonas sulfidaeris (97.9%), Halomonas zhaodongensis (97.8%), Halomonas songnenensis (97.6%), Halomonas hydrothermalis (97.4%), Halomonas subterranea (97.3%), Halomonas salicampi (97.1%), and Halomonas arcis (97.0%). DNA–DNA hybridization ( 10%) of strain QX-1 T are C16:0 (25.5%), C17:0 cyclo (14.0%), C19:0 cyclo ω8c (18.7%), and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c, 18.1%). The polar lipids of strain QX-1 T are mainly diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid, unidentified aminophospholipid, and five unidentified lipids. The main respiratory quinone is Q-9. The G + C content of its chromosomal DNA is 54.4 mol%. Its fatty acid profile, respiratory quinones, and G + C content also support the placement of QX-1 T in the genus Halomonas. These phylogenetic, phenotypic, and chemotaxonomic analyses indicate that QX-1 T is a novel species, for which the name Halomonas maris is proposed. The type strain is QX-1 T (= MCCC 1A17875T = KCTC 82198 T = NBRC 114670 T).

Colwellia psychrerythraea is a marine psychrophilic bacterium known for its remarkable ability to maintain activity during long-term exposure to extreme subzero temperatures and correspondingly high salinities in sea ice. These microorganisms must have adaptations to both high salinity and low temperature to survive, be metabolically active, or grow in the ice. Here, we report on an experimental design that allowed us to monitor culturability, cell abundance, activity and proteomic signatures of C. psychrerythraea strain 34H (Cp34H) in subzero brines and supercooled sea water through long-term incubations under eight conditions with varying subzero temperatures, salinities and nutrient additions. Shotgun proteomics found novel metabolic strategies used to maintain culturability in response to each independent experimental variable, particularly in pathways regulating carbon, nitrogen and fatty acid metabolism. Statistical analysis of abundances of proteins uniquely identified in isolated conditions provide metabolism-specific protein biosignatures indicative of growth or survival in either increased salinity, decreased temperature, or nutrient limitation. Additionally, to aid in the search for extant life on other icy worlds, analysis of detected short peptides in −10°C incubations after 4 months identified over 500 potential biosignatures that could indicate the presence of terrestrial-like cold-active or halophilic metabolisms on other icy worlds.

The applicability of extremophilic amylases in hydrolyzing food waste for bioethanol production has not been investigated much. The current study aims to extract amylases from halophilic bacteria i...

Vibrio fluvialis is a halophilic bacterium frequently found in estuarine and coastal waters environments. The strain 362.3 was isolated from Mussismilia braziliensis coral of Abrolhos Bank. In this study, to gain insights into the marine adaptation in V. fluvialis, we sequenced the genome of 362.3 strain, which comprised 4,607,294 bp with a G + C content of 50.2%. In silico analysis showed that V. fluvialis 362.2 encodes genes related to chitin catabolic pathway, iron metabolism, osmotic stress and membrane transport.

Every year, new organisms that survive and colonize adverse environments are discovered and isolated. Those organisms, called extremophiles, are distributed throughout the world, both in aquatic and terrestrial environments, such as sulfurous marsh waters, hydrothermal springs, deep waters, volcanos, terrestrial hot springs, marine saltern, salt lakes, among others. According to the ecosystem inhabiting, extremophiles are categorized as thermophiles, psychrophiles, halophiles, acidophiles, alkalophilic, piezophiles, saccharophiles, metallophiles and polyextremophiles. They have developed chemical adaptation strategies that allow them to maintain their cellular integrity, altering physiology or improving repair capabilities; one of them is the biosynthesis of extracellular polysaccharides (EPS), which constitute a slime and hydrated matrix that keep the cells embedded, protecting from environmental stress (desiccation, salinity, temperature, radiation). EPS have gained interest; they are explored by their unique properties such as structural complexity, biodegradability, biological activities, and biocompatibility. Here, we present a review concerning the biosynthesis, characterization, and potential EPS applications produced by extremophile microorganisms, namely, thermophiles, halophiles, and psychrophiles. A bibliometric analysis was conducted, considering research articles published within the last two decades. Besides, an overview of the culture conditions used for extremophiles, the main properties and multiple potential applications of their EPS is also presented.

The available information on de novo synthesized compatible solutes in response to high medium salinity by bacteria of the Chromohalobacter genus is limited to studies of the mesophilic moderately halophilic strain Chromohalobacter salexigens DSM 3043T. Therefore, there is a need for studies of representatives of other species of the Chromohalobacter genus of the Halomonadaceae family. A moderately halophilic psychrotolerant bacterium, strain N1, closely related to the species Chromohalobacter japonicus was isolated from the salt crust of a rock salt waste pile in Berezniki, Perm Krai, Russia. An intracellular pool of compatible solutes of strain N1 was investigated by NMR spectroscopy. Cells grown in the presence of 5% NaCl at optimal growth temperature (28 °C) accumulated ectoine, glutamate, N(4)-acetyl-l-2,4-diaminobutyrate (NADA), alanine, trehalose, hydroxyectoine, and valine. Such a combination of compatible solutes is unique and distinguishes the strain from C. salexigens DSM 3043T. Hyperosmotic stress induced by 15% NaCl caused the accumulation of ectoine, NADA, and hydroxyectoine but led to a decrease in the amount of alanine, valine, and trehalose. The intracellular pool of glutamate was not significantly changed. A reduction of the growth temperature from 28 to 5 °C led to an increase in the amount of ectoine, NADA, trehalose, and hydroxyectoine. Ectoine was the major compatible solute.

Sabkhas in Kuwait are unique hypersaline marine environments under-explored for bacterial community composition and bioprospecting. The 16S rRNA sequence analysis of 46 isolates with distinct morphology from two Kuwait sabkhas recovered 11 genera. Phylum Firmicutes dominated these isolates, and Bacillus (32.6%) was recovered as the dominant genera, followed by Halococcus (17.4%). These isolates were moderately halophilic, and some of them showed tolerance and growth at extreme levels of salt (20%), pH (5 and/or 11), and temperature (55 °C). A higher percentage of isolates harbored protease (63.0), followed by DNase (41.3), amylase (41.3), and lipase (32.6). Selected isolates showed antimicrobial activity against E. faecalis and isolated Halomonas shengliensis, and Idiomarina piscisalsi harbored gene coding for dNDP-glucose 4,6-dehydratase (Glu 1), indicating their potential to produce biomolecules with deoxysugar moieties. Palmitic acid or oleic acid was the dominant fatty acid, and seven isolates had some polyunsaturated fatty acids (linolenic or γ-linolenic acid). Interestingly, six isolates belonging to Planococcus and Oceanobacillus genus produced squalene, a bioactive isoprenoid molecule. Their content increased 30-50% in the presence of Terbinafine. The potential bioactivities and extreme growth conditions make this untapped bacterial diversity a promising candidate for future bioprospecting studies.

Concurrent osmotic and chaotropic stress make MgCl2 -rich brines extremely inhospitable environments. Understanding the limits of life in these brines is essential to the search for extraterrestrial life on contemporary and relict ocean worlds, like Mars, which could host similar environments. We sequenced environmental 16S rRNA genes and quantified microbial activity across a broad range of salinity and chaotropicity at a Mars-analogue salt harvesting facility in Southern California, where seawater is evaporated in a series of ponds ranging from kosmotropic NaCl brines to highly chaotropic MgCl2 brines. Within NaCl brines, we observed a proliferation of specialized halophilic Euryarchaeota, which corresponded closely with the dominant taxa found in salterns around the world. These communities were characterized by very slow growth rates and high biomass accumulation. As salinity and chaotropicity increased, we found that the MgCl2 -rich brines eventually exceeded the limits of microbial activity. We found evidence that exogenous genetic material is preserved in these chaotropic brines, producing an unexpected increase in diversity in the presumably sterile MgCl2 -saturated brines. Because of their high potential for biomarker preservation, chaotropic brines could therefore serve as repositories of genetic biomarkers from nearby environments (both on Earth and beyond) making them prime targets for future life-detection missions.

A Gram-staining-negative, aerobic, flagellated, motile, rod-shaped, halophilic bacterium QX-2T was isolated from the deep-sea sediment of the Southwest Indian Ocean at a depth of 2699 m. Growth of the QX-2T bacteria was observed at 4–50 °C (optimum 30 °C), pH 5.0–12.0 (optimum pH 6.0) and 0%–30% NaCl (w/v) [optimum 4% (w/v)]. 16S rRNA gene sequencing revealed that strain QX-2T has the closest relationship with Halomonas titanicae DSM 22872T (98.2%). Phylogeny analysis classified the strain QX-2T into the genus Halomonas. The average nucleotide identity and DNA–DNA hybridization values between strain QX-2T and related type strains were lower than the currently accepted new species definition standards. Principal fatty acids (> 10%) determined were C16:0 (12.41%), C12:0-3OH (25.15%), summed feature 3 (C16:1 ω7c and/or C16:1 ω6c, 11.55%) and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c, 16.06%). Identified polar lipids in strain QX-2T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid, unidentified aminophospholipid and five unidentified lipids (L1–L5). The main respiratory quinone was Q-9. The content of DNA G+C was determined to be 54.34 mol%. The results of phylogenetic analysis, phenotypic analysis and chemotaxonomic studies showed that strain QX-2T represents a novel species within the genus Halomonas, for which the name Halomonas sedimenti sp. nov. is proposed, with the type strain QX-2T (MCCC 1A17876T = KCTC 82199T).

Background Group II introns are mobile genetic elements used as efficient gene targeting tools. They function as both ribozymes and retroelements. Group IIC introns are the only class reported so far to be associated with integrons. In order to identify group II introns linked with integrons and CALINS (cluster of attC sites lacking a neighboring integron integrase) within halophiles, we mined for integrons in 28 assembled metagenomes from hypersaline environments and publically available 104 halophilic genomes using Integron Finder followed by blast search for group II intron reverse transcriptases (RT)s. Results We report the presence of different group II introns associated with integrons and integron-related sequences denoted by UHB.F1, UHB.I2, H.ha.F1 and H.ha.F2. The first two were identified within putative integrons in the metagenome of Tanatar-5 hypersaline soda lake, belonging to IIC and IIB intron classes, respectively at which the first was a truncated intron. Other truncated introns H.ha.F1 and H.ha.F2 were also detected in a CALIN within the extreme halophile Halorhodospira halochloris, both belonging to group IIB introns. The intron-encoded proteins (IEP) s identified within group IIB introns belonged to different classes: CL1 class in UHB.I2 and bacterial class E in H.ha.Fa1 and H.ha.F2. A newly identified insertion sequence (ISHahl1) of IS200/605 superfamily was also identified adjacent to H. halochloris CALIN. Finally, an abundance of toxin-antitoxin (TA) systems was observed within the identified integrons. Conclusion So far, this is the first investigation of group II introns within integrons in halophilic genomes and metagenomes from hypersaline environments. We report the presence of group IIB introns associated with integrons or CALINs. This study provides the basis for understanding the role of group IIB introns in the evolution of halophiles and their potential biotechnological role.

Endoglucanase, particularly those, which can withstand extreme conditions are in demand in different industrial settings. In this direction, a halophilic cellulolytic bacterial strain EN1 was isolated from decomposed wood particles of India’s largest inland hypersaline Sambhar Lake in Rajasthan. Based on 16S rRNA gene sequence homology, the bacterium was identified as Salisediminibacterium halotolerans. It constitutively secretes extracellular endoglucanase in heterotrophic culture supernatant supplemented with or without carboxy-methyl cellulose. EN1 endoglucanase is active at pH 8.0–11.0, and 10–30% NaCl with optimum values of pH 11.0, and 25% NaCl. Under these optimum conditions, the enzyme retained up to 90% activity for 8 h. Activity was enhanced by some metal ions (5 mM) in order of Cu2+ (273%), Ni2+ (139%) and Fe2+ (125%); and decreased by Mg2+ (72%) and EDTA (56%). The enzyme was stable in different organic solvents (30% v/v), namely ethanol (108%), hexane (95%), methanol (93%), and iso-propanol (92%). The endoglucanase was effectively used for in situ saccharification of alkali-pretreated rice straw with 50 µg mL−1 reducing ends released after 120 h. These unique features of the extracellular endoglucanase reported for the first time from the genera Salisediminibacterium indicate its prospects in different industrial settings particularly for bioethanol production.

Bu çalışmada, 16S rRNA geni hedefli yaklaşımlar kullanılarak prokaryotik grupların Tuz Gölü, Ayvalık ve Tuzlagözü güneş tuzlalarındaki dağılımı araştırılmıştır. Numunelerdeki prokaryotik taksonların nispi bolluğu, yüksek-verimli dizileme kullanılarak saptanmıştır. Haloquadratum ile ilişkili operasyonel taksonomik birimler (OTU'lar) MiSeq okumalarında en bol saptananlardı. Nanohaloarchaeota-ilişkili OTU’lar Ayvalık ve Tuzlagözü güneş tuzlalarında nadirdi (, IIn this study, distribution of the prokaryotic groups in Tuz Lake, Ayvalık and Tuzlagözü solar salterns was investigated using 16S rRNA gene targeted approaches. The relative abundance of prokaryotic taxa in the samples was detected by using high-throughput sequencing. Operational taxonomic units (OTUs) associated with Haloquadratum were the most abundant in MiSeq reads. Nanohaloarchaeota-related OTUs were rare (

A Gram staining-negative, halophilic, aerobic, non-motile bacteria, designated strain WN018T, were isolated from the natural saline–alkali wetland soil of Binhai new district, Tianjin, China (38°46′N, 117°13′E). Cells of strain WN018T were short rod-shaped, 0.3–0.4 µm wide and 0.5–1.9 µm long, and growth occurred optimally at 30–33 °C, pH 7.5–8.0, and in the presence of 4–8% (w/v) NaCl. Based on 16S rRNA gene sequence analysis, the isolates could be affiliated to the genus Halomonas, exhibiting highest sequence similarity of 97.50% to Halomonas venusta DSM 4743T. The DNA G+C content of the strain was 63.8%. The distinct phylogenetic position and phenotypic traits distinguished the novel isolate from its nearest neighbors. The major respiratory quinone of strain WN018T was Q-9 (91.0%) and Q-8 (9.0%), and the dominant fatty acids were C16:0, C14:0, C10:0, C12:0 3-OH. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), three phospholipids (PL), aminolipid (AL), and two unidentified lipids (L). The average nucleotide identity (ANI) based on whole-genome sequences of strain WN018T and Halomonas hydrothermalis DSM 15725T was 93.02%, and the dDDH value between these two strains was determined to be 49.7%. Therefore, we propose a novel species in the genus Halomonas to accommodate the novel isolate: Halomonas humidisoli sp. nov. (type strain WN018T = ACCC 19975T = KCTC 52854T).

Ten species of halophilic gastropods of the genus Caspiohydrobia are identified for the first time from the Lantsug and Gor’kaya Rechka salt rivers, tributaries of Lakes Elton and Baskunchak, respectively. The genus was previously known from the Caspian and Aral seas and some salt water bodies of Kazakhstan and Chelyabinsk and Kurgan regions. Since the hydrological and hydrochemical regimes of salt rivers critically depend on climatic conditions, Caspiohydrobia living in these habitats can be considered endangered.

A mannan-degrading halophilic archaeal strain, MD130-1T, was isolated from a commercial salt sample. Cells were motile, rod-shaped, and stained Gram-negative. Colonies were pink pigmented. Strain MD130-1T was able to grow at 1.5–4.6 M NaCl (optimum, 3.6 M) at pH 6.0–8.0 (optimum, pH 7.0) and at 25–50 °C (optimum, 40 °C). The DNA G+C content was 62.1 mol% (genome). The orthologous 16S rRNA gene sequence showed the highest similarity (99.4 %) to those of Haloarcula japonica JCM 7785T and Haloarcula hispanica JCM 8911T. The values of genome relatedness between strain MD130-1T and Haloarcula species were 84.33–85.96 % in ANIb and 30.4–32.9 % using GGDC formula 2. The polar lipids of strain MD130-1T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and triglycosyl diether-2. Based on the results of phenotypic and phylogenetic analyses, the strain represents a new species of the genus Haloarcula , for which the name Haloarcula mannanilytica sp. nov. is proposed. The type strain is MD130-1T (=JCM 33835T=KCTC 4287T) isolated from commercial salt made in Ishikawa prefecture, Japan.

Background: Due to the last two decades of drought disaster, which resulted in the loss of the main part of Urmia Lake water and changed the natural conditions of an environment, especially ionic strength. Objective: We aimed to isolate and characterize halophilic and halotolerant bacteria in Urmia Lake, Iran, 2015. Urmia Lake is a permanent and salty inland lake located in the Azerbaijan region in northwestern Iran. Methods: Sampling was carried out in multiple water-filled locations of the lake. Liquid basal media for the enrichment of bacteria was successively applied and colonies were isolated by the plating method. Isolates were then distinguished based on differences in colony, Gram staining, microscopic shape, and biochemical properties. Results: One chemolithotrophic isolate belonging to Thiobacillus thioparus and 41 heterotrophic isolates were obtained. The 16S rRNA gene sequences showed that all 42 isolates belong to the genera Kocuria (21.42%), Marinobacter (11.90%), Micrococcus (11.90%), Thalassobacillus (11.90%), Bacillus (11.90%), Halomonas (7.14%) and Thiobacillus (2.38%). Conclusion: Based on 16S rRNA similarity, 5 of 41 isolates showed the potential to be introduced as new species. The dominant genera with abounded frequency were found to be Kocuria, Bacillus and Thalassobacillus genera.