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Dethiobacter alkaliphilus strain AHT1T is an anaerobic, sulfidogenic, moderately salt-tolerant alkaliphilic chemolithotroph isolated from hypersaline soda lake sediments in northeastern Mongolia. It is a Gram-positive bacterium with low GC content, within the phylum Firmicutes. Here we report its draft genome sequence, which consists of 34 contigs with a total sequence length of 3.12 Mbp. D. alkaliphilus strain AHT1T was sequenced by the Joint Genome Institute (JGI) as part of the Community Science Program due to its relevance to bioremediation and biotechnological applications. [ABSTRACT FROM AUTHOR]

A novel multi-domain high molecular xylanase coding gene (xynSL3) was cloned from Alkalibacterium sp. SL3, an alkaliphilic bacterial strain isolated from the sediment of soda lake Dabusu. The deduced XynSL3 is composed of a putative signal peptide, three tandem domains of carbohydrate binding module (CBM) family 22, a catalytic domain of glycosyl hydrolase (GH) family 10 and a domain of CBM9. XynSL3 shares the highest identity of 66% to a hypothetical protein from Alkalibacterium sp. AK22 and has low identities (33-45%) with other functionally characterized xylanases. The gene xynSL3 was expressed heterologously in Escherichia coli and the recombinant enzyme demonstrated some particular characteristics. Purified recombinant XynSL3 (rXynSL3) was highly active and stable over the neutral and alkaline pH ranges from 7.0 to 12.0, with maximum activity at pH 9.0 and around 45% activity at pH 12.0. It had an apparent temperature optimum of 55°C and was stable at 50°C. The rXynSL3 was highly halotolerant, retaining more than 60% activity with 3 M NaCl and was stable at up to a 4 M concentration of NaCl. The hydrolysis products of rXynSL3 from corncob xylan were mainly xylobiose and xylotetraose. The activity of rXynSL3 was enhanced by Ca2+ and it has strong resistance to sodium dodecyl sulfate (SDS). This multi-domain, alkaline and salt-tolerant enzyme has great potential for basic research and industrial applications such as the biobleaching of paper pulp and production of xylo-oligosaccharides (XOS). [ABSTRACT FROM AUTHOR]

Lacustrine sediments of impact craters form valuable climate archives, although chemical evolution and changes in the catchment area potentially superimpose, distort, or obliterate primary climate signals. The 15 Ma Nördlinger Ries in southern Germany, one of the most intensively studied terrestrial impact structures, harbors a well-preserved but controversially interpreted lacustrine sedimentary fill. While earlier studies proposed a climate-driven development from a playa to a mesosaline soda lake (Units A and B), which then decreased in salinity (Units C and D), new investigations suggest a chemical evolution from a playa and soda lake (Units A-C) to a mesosaline halite lake (Unit D), which then turned into a hypersaline halite lake, until an outlet formed. However, problems in the stratigraphic correlation of basin center and margin sediments impeded the recognition of the hypothetical soda to halite lake transition to date. A new drilling in the central crater now provides a solution for the problem. Unit C still comprises analcime-rich dolomite marl with reversely correlated δC and δO values, thereby reflecting a shallow, highly alkaline, saline meromictic lake (Na-Mg-CO-SO). In turn, Unit D is characterized by a change to cycles composed of lignite, diatomite, claystone, marl, and limestone. Gypsum pseudomorphs at the cycle tops indicate saline lake water (Na-Mg-Cl-SO) with increased Ca concentrations. Reworked, previously aragonitic, green algal tubes prove that early parts of Unit D sediments formed contemporaneously to basin margin green algal bioherms, contrary to previous assumptions. Therefore, the change from a highly alkaline soda lake to a mesosaline halite lake reflects increasing influx of waters from the Bunte Breccia into the lake, while suevite-derived weathering solutions decreased. Low-salinity conditions during Unit D are temporary phases during lake-level rise at the beginning of short-term cycles, whereas stable oxygen isotope ratios indicate meso- to hypersaline conditions at cycle tops. However, the long-term increase in salinity leading to continuous hypersaline conditions is only preserved in carbonates at the crater rim. [ABSTRACT FROM AUTHOR]

Five halophilic archaeal strains (AGai3-5 T , KZCA101 T , CGA3 T , WLHS1 T and WLHSJ1 T ) were isolated from salt lakes and soda lakes in PR China. These strains had low 16S rRNA gene similarities (91.3-96.0 %) to closely related species of the family Natrialbaceae and may represent a new genus of the family. Phylogenetic and phylogenomic analyses revealed that these strains formed a distinct clade, separate from the nearby genera Natronobiforma and Saliphagus . The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity (AAI) values among these five strains and the current members of the family Natrialbaceae were 72-90, 20-42 and 62-91 %, respectively, clearly below the threshold values for species demarcation. According to the critical value of AAI (≤76 %) proposed to differentiate genera within the family Natrialbaceae , it was further indicated that these strains represented a novel genus within the family. These strains could be distinguished from the related genera according to differential phenotypic characteristics. The major lipids of these strains were phosphatidic acid (PA), phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, mannosyl glucosyl diether (DGD-PA), sulphated DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. The phenotypic, chemotaxonomic, phylogenetic and phylogenomic features indicated that strains AGai3-5 T (=CGMCC 1.16078 T =JCM 33549 T ), KZCA101 T (=CGMCC 1.17431 T =JCM 35074 T ), CGA3 T (=CGMCC 1.17463 T =JCM 34318 T ), WLHS1 T (=CGMCC 1.13780 T =JCM 33562 T ) and WLHSJ1 T (=CGMCC 1.13784 T =JCM 33563 T ) represent five novel species of a new genus within the family Natrialbaceae , named Natronosalvus halobius gen. nov., sp. nov., Natronosalvus caseinilyticus sp. nov., Natronosalvus vescus sp. nov., Natronosalvus rutilus sp. nov. and Natronosalvus amylolyticus sp. nov., respectively.

Lonar Lake is a hypersaline and hyperalkaline soda lake and the only meteorite impact crater in the world created in the basalt rocks. Although culture-dependent studies have been reported, the comprehensive understanding of microbial community composition and structure of Lonar Lake remain obscure. In the present study, microbial community structure associated with Lonar Lake sediment and water samples was investigated using high throughput sequencing. Microbial diversity analysis revealed the existence of diverse, yet near consistent community composition. The predominance of bacterial phyla Proteobacteria (30%) followed by Actinobacteria (24%), Firmicutes (11%) and Cyanobacteria (5%) was observed. Bacterial phylum Bacteroidetes (1.12%), BD1-5 (0.5%), Nitrospirae (0.41%) and Verrucomicrobia (0.28%) were detected as relatively minor populations in Lonar Lake ecosystem. Within Proteobacteria, Gammaproteobacteria represented the most abundant population (21-47%) among all the sediments and as a minor population in water samples. Bacterial members Proteobacteria and Firmicutes were present significantly higher (p≥0.05) in sediment samples, whereas members of Actinobacteria, Candidate_division_TM7 and Cyanobacteria (p≥0.05) were significantly abundant in water samples. It was noted that compared to other hypersaline soda lakes, Lonar Lake samples formed one distinct cluster, suggesting a different microbial community composition and structure. The present study reports for the first time the different composition of indigenous microbial communities between the sediment and water samples of Lonar Lake. Having better insight of community structure of this Lake ecosystem could be useful in understanding the microbial role in the geochemical cycle for future functional exploration of the unique hypersaline Lonar Lake.

The genus Belliella belongs to the family Cyclobacteriaceae (order Cytophagales , phylum Bacteroidota ) and harbours aerobic chemoheterotrophic bacteria. Members of this genus were isolated from various aquatic habitats, and our analysis based on global amplicon sequencing data revealed that their relative abundance can reach up to 5-10 % of the bacterioplankton in soda lakes and pans. Although a remarkable fraction of the most frequent genotypes that we identified from continental aquatic habitats is still uncultured, five new alkaliphilic Belliella strains were characterized in detail in this study, which were isolated from three different soda lakes and pans of the Carpathian Basin (Hungary). Cells of all strains were Gram-stain-negative, obligate aerobic, rod-shaped, non-motile and non-spore-forming. The isolates were oxidase- and catalase-positive, red-coloured, but did not contain flexirubin-type pigments; they formed bright red colonies that were circular, smooth and convex. Their major isoprenoid quinone was MK-7 and the predominant fatty acids were iso-C 15 : 0 , iso-C 17 : 0 3-OH and summed feature 3 containing C 16 : 1  ω 6 c and/or C 16 : 1  ω 7 c . The polar lipid profiles contained phosphatidylethanolamine, an unidentified aminophospholipid, an unidentified glycolipid, and several unidentified lipids and aminolipids. Based on whole-genome sequences, the DNA G+C content was 37.0, 37.1 and 37.8 mol % for strains R4-6 T , DMA-N-10a T and U6F3 T , respectively. The distinction of three new species was confirmed by in silico genomic comparison. Orthologous average nucleotide identity (<85.4 %) and digital DNA-DNA hybridization values (<38.9 %) supported phenotypic, chemotaxonomic and 16S rRNA gene sequence data and, therefore, the following three novel species are proposed: Belliella alkalica sp. nov. (represented by strains R4-6 T =DSM 111903 T =JCM 34281 T =UCCCB122 T and S4-10), Belliella calami sp. nov. (DMA-N-10a T =DSM 107340 T =JCM 34280 T =UCCCB121 T ) and Belliella filtrata sp. nov. (U6F3 T =DSM 111904 T =JCM 34282 T =UCCCB123 T and U6F1). Emended descriptions of species Belliella aquatica , Belliella baltica , Belliella buryatensis , Belliella kenyensis and Belliella pelovolcani are also presented.

Background: Soda lakes are unique environments in terms of their physical characteristics and the biology they harbour. Although well studied with respect to their microbial composition, their viral compositions have not, and consequently few bacteriophages that infect bacteria from haloalkaline environments have been described. Methods: Bacteria were isolated from sediment samples of lakes Magadi and Shala. Three phages were isolated on two different Bacillus species and one Paracoccus species using agar overlays. The growth characteristics of each phage in its host was investigated and the genome sequences determined and analysed by comparison with known phages. Results: Phage Shbh1 belongs to the family Myoviridae while Mgbh1 and Shpa belong to the Siphoviridae family. Tetranucleotide usage frequencies and G + C content suggests that Shbh1 and Mgbh1 do not regularly infect, and have therefore not evolved with, the hosts they were isolated on here. Shbh1 was shown capable of infecting two different Bacillus species from the two different lakes demonstrating its potential broad-host range. Comparative analysis of their genome sequence with known phages revealed that, although novel, Shbh1 does share substantial amino acid similarity with previously described Bacillus infecting phages (Grass, phiNIT1 and phiAGATE) and belongs to the Bastille group, while Mgbh1 and Shpa are highly novel. Conclusion: The addition of these phages to current databases should help with metagenome/metavirome annotation efforts. We describe a highly novel Paracoccus infecting virus (Shpa) which together with NgoΦ6 and vB_PmaS_IMEP1 is one of only three phages known to infect Paracoccus species but does not show similarity to these phages. [ABSTRACT FROM AUTHOR]

Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune, India Soda lake is hyper alkaline and saline habitat located in closed craters with high evaporation rate. In current study fungal diversity from water and sediment samples of a soda lake (Lonar lake) located in Buldhana district of Maharashtra, India was investigated using extensive culturomics approach and mimicking the natural conditions of Lonar lake in culture media. A total of 104 diverse isolates of extremophilic fungi were recovered from this study and phylogenetically characterized by internal transcribed spacer (ITS) region sequencing. In addition, due to important role of phenol oxidase, and peroxidase in degradation of toxic phenol, lignin, etc., all isolated pure cultures were also screened for extracellular phenol oxidase and peroxidase production potential. Diversity analysis indicated that different groups of extremophilic fungi are present in the water and sediment samples of Lonar lake. A total of 38 species of fungi belonging to 18-different genera were recovered. Out of 104 isolates 32 showed =97% sequences similarity, which were morphologically different and could be potential novel isolates of extremophilic fungi. However, out of 104 isolates only 14 showed the extracellular phenol oxidase production potentials at alkaline pH. Curvularia sp. strain MEF018 showed highest phenol oxidase production at alkaline condition and had low sequence similarity with previously characterized species (96% with Curvularia pseudorobusta). Taxonomic characterization (morphological and physiological) and multi locus sequence analysis (MLSA) using combined alignment of ITS-LSU-gpd of strain MEF018 showed that it is a novel species of the genus Curvularia and hence proposed as Curvularia lonarensis sp. nov. [ABSTRACT FROM AUTHOR]

Desulfurivibrio alkaliphilus strain AHT2T is a strictly anaerobic sulfidogenic haloalkaliphile isolated from a composite sediment sample of eight hypersaline alkaline lakes in the Wadi al Natrun valley in the Egyptian Libyan Desert. D. alkaliphilus AHT2T is Gram-negative and belongs to the family Desulfobulbaceae within the Deltaproteobacteria. Here we report its genome sequence, which contains a 3.10 Mbp chromosome. D. alkaliphilus AHT2T is adapted to survive under highly alkaline and moderately saline conditions and therefore, is relevant to the biotechnology industry and life under extreme conditions. For these reasons, D. alkaliphilus AHT2T was sequenced by the DOE Joint Genome Institute as part of the Community Science Program. [ABSTRACT FROM AUTHOR]

During a screening for novel and biotechnologically useful bacteria in haloalkaline lakes, strain No.156 was isolated from a sediment sample from lake Elmenteita in the African Rift Valley and studied by a polyphasic taxonomic approach. The strain was observed to form yellow aerial and substrate mycelia; optimal growth was found to be at 30-35 °C in salt concentrations of 6-9 % (w/v) and at pH 7-9. The DNA G+C content of the novel strain was 71 mol%. Analysis of 16S rRNA sequences indicated that the isolate belongs to the genus Nocardiopsis with sequence similarities below 98 % to the type strains of all other representatives of the genus. Mycolic acids were not detected in whole cell methanolysates. The peptidoglycan was found to contain meso-diaminopimelic acid as the diamino acid with no diagnostic sugars. The main polar lipids were identified as phosphatidylmethylethanolamine, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol but no diphosphatidylglycerol. The predominant menaquinones were MK-11(H), MK-11(H), MK-10(H) and MK-10(H). Cellular fatty acids were found to consist of saturated and monounsaturated iso- and anteiso-branched acids with 16-18 C-length, tuberculostearic acid (Me18:0), and straight-chain saturated (16:0, 18:0) acids. These characteristics match those of the genus Nocardiopsis. Based on 16S rRNA gene sequence analysis and phenotypic characteristics, a novel species with the name Nocardiopsis mwathae is proposed. The type strain is No.156 (=DSM 46659 = CECT 8552). The INSDC accession number for the 16S rRNA gene sequence of strain No.156 is KF976731. [ABSTRACT FROM AUTHOR]