Habitat distribution of the genus Belliella in continental waters and the description of Belliella alkalica sp. nov., Belliella calami sp. nov. and Belliella filtrata sp. nov.

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-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 containing C16 : 1 ω6c and/or C16 : 1 ω7c. 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 R4-6T, DMA-N-10aT and U6F3T, 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 R4-6T=DSM 111903T=JCM 34281T=UCCCB122T and S4-10), Belliella calami sp. nov. (DMA-N-10aT=DSM 107340T=JCM 34280T=UCCCB121T) and Belliella filtrata sp. nov. (U6F3T=DSM 111904T=JCM 34282T=UCCCB123T and U6F1). Emended descriptions of species Belliella aquatica, Belliella baltica, Belliella buryatensis, Belliella kenyensis and Belliella pelovolcani are also presented.

Kinetic characterization of a new phenol degrading Acinetobacter towneri strain isolated from landfill leachate treating bioreactor.

The objective of this study was to establish and to mathematically describe the phenol degrading properties of a new Acinetobacter towneri CFII-87 strain, isolated from a bioreactor treating landfill leachate. For this purpose, the biokinetic parameters of phenol biodegradation at various initial phenol concentrations of the A. towneri CFII-87 strain have been experimentally measured, and four different mathematical inhibition models (Haldane, Yano, Aiba and Edwards models) have been used to simulate the substrate-inhibited phenol degradation process. The results of the batch biodegradation experiments show that the new A. towneri CFII-87 strain grows on and metabolizes phenol up to 1000 mg/L concentration, manifests significant substrate inhibition and lag time only at concentrations above 800 mg/L phenol, and has a maximum growth rate at 300 mg/L initial phenol concentration. The comparison of the model predictions with the experimental phenol and biomass data revealed that the Haldane, Aiba and Edwards models can be used with success to describe the phenol biodegradation process by A. towneri CFII-87, while the Yano model, especially at higher initial phenol concentrations, fails to describe the process. The best performing inhibition model was the Edwards model, presenting correlation coefficients of R2 > 0.98 and modelling efficiency of ME > 0.94 for the prediction of biomass and phenol concentrations on the validation datasets. The calculated biokinetic model parameters place this new strain among the bacteria with the highest tolerance towards phenol. The results suggest that the A. towneri CFII-87 strain can potentially be used in the treatment of phenolic wastewaters.

Anion-type modulates the effect of salt stress on saline lake bacteria.

Beside sodium chloride, inland saline aquatic systems often contain other anions than chloride such as hydrogen carbonate and sulfate. Our understanding of the biological effects of salt composition diversity is limited; therefore, the aim of this study was to examine the effect of different anions on the growth of halophilic bacteria. Accordingly, the salt composition and concentration preference of 172 strains isolated from saline and soda lakes that differed in ionic composition was tested using media containing either carbonate, chloride or sulfate as anion in concentration values ranging from 0 to 0.40 mol/L. Differences in salt-type preference among bacterial strains were observed in relationship to the salt composition of the natural habitat they were isolated from indicating specific salt-type adaptation. Sodium carbonate represented the strongest selective force, while majority of strains was well-adapted to growth even at high concentrations of sodium sulfate. Salt preference was to some extent associated with taxonomy, although variations even within the same bacterial species were also identified. Our results suggest that the extent of the effect of dissolved salts in saline lakes is not limited to their concentration but the type of anion also substantially impacts the growth and survival of individual microorganisms.

Comparative Investigation of 15 Xenobiotic-Metabolizing N-Acetyltransferase (NAT) Homologs from Bacteria.

Arylamines constitute a large group of industrial chemicals detoxified by certain bacteria through conjugation reactions catalyzed by N-acetyltransferase (NAT) enzymes. NAT homologs, mostly from pathogenic bacteria, have been the subject of individual studies that do not lend themselves to direct comparisons. By implementing a practicable pipeline, we carried out a comparative investigation of 15 NAT homologs from 10 bacteria, mainly bacilli, streptomycetes, and one alphaproteobacterium. The new homologs were characterized for their sequence, phylogeny, predicted structural features, substrate specificity, thermal stability, and interaction with components of the enzymatic reaction. Bacillus NATs demonstrated the characteristics of xenobiotic metabolizing N-acetyltransferases, with the majority of homologs generating high activities. Nonpathogenic bacilli are thus proposed as suitable mediators of arylamine bioremediation. Of the Streptomyces homologs, the NAT2 isoenzyme of S. venezuelae efficiently transformed highly toxic arylamines, while the remaining homologs were inactive or generated low activities, suggesting that xenobiotic metabolism may not be their primary role. The functional divergence of Streptomyces NATs was consistent with their observed sequence, phylogenetic, and structural variability. These and previous findings support classification of microbial NATs into three groups. The first includes xenobiotic metabolizing enzymes with dual acetyl/propionyl coenzyme A (CoA) selectivity. Homologs of the second group are more rarely encountered, acting as malonyltransferases mediating specialized ecological interactions. Homologs of the third group effectively lack acyltransferase activity, and their study may represent an interesting research area. Comparative NAT enzyme screens from a broad microbial spectrum may guide rational selection of homologs likely to share similar biological functions, allowing their combined investigation and use in biotechnological applications. IMPORTANCE Arylamines are encountered as industrial chemicals or by-products of agrochemicals that may constitute highly toxic contaminants of soils and groundwaters. Although such chemicals may be recalcitrant to biotransformation, they can be enzymatically converted into less toxic forms by some bacteria. Therefore, exploitation of the arylamine detoxification capabilities of microorganisms is investigated as an effective approach for bioremediation. Among microbial biotransformations of arylamines, enzymatic conjugation reactions have been reported, including NAT-mediated N-acetylation. Comparative investigations of NAT enzymes across a range of microorganisms can be laborious and expensive, so here we present a streamlined methodology for implementing such work. We compared 15 NAT homologs from nonpathogenic, free-living bacteria of potential biotechnological utility, mainly Terrabacteria, which are known for their rich secondary and xenobiotic metabolism. The analysis allowed insights into the evolutionary and functional divergence of bacterial NAT homologs, combined with assessment of their fundamental structural and enzymatic differences and similarities.

Sapientia aquatica gen. nov., sp. nov., isolated from a crater lake.

A new aerobic betaproteobacterium, strain SA-152T, was isolated from the water of a crater lake. 16S rRNA gene sequence analysis revealed that strain SA-152T belonged to the family Oxalobacteraceae (order Burkholderiales) and was phylogenetically related to Solimicrobium silvestre S20-91T with 97.09 % and to Herminiimonas arsenicoxydans ULPAs1T with 96.00 % 16S rRNA gene pairwise sequence similarity. Cells of strain SA-152T were rod-shaped, non-motile, oxidase-negative and catalase-positive. Its fatty acid profile was dominated by two fatty acids, C16 : 1 ω7c and C16 : 0, the major respiratory quinones were Q-8 and Q-7, and the main polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The G+C content of the genomic DNA of strain SA-152T was 48.3 mol%. The new bacterium can be distinguished from closely related genera Solimicrobium, Herminiimonas, Rugamonas and Undibacterium based on its non-motile and oxidase-negative cells. On the basis of the phenotypic, chemotaxonomic and genomic data, strain SA-152T is considered to represent a novel species of a new genus, for which the name Sapientia aquatica gen. nov., sp. nov. is proposed. The type strain of Sapientia aquatica is SA-152T (=DSM 29805T=NCAIM B.02613T).

Microbiological investigations of two thermal baths in Budapest, Hungary. Report: effect of bathing and pool operation type on water quality.

In Hungary, which is famous for its thermal baths, according to the regulations, waters are investigated in hygienic aspects with standard cultivation methods. In the present study, two thermal baths were investigated (the well and three different pool waters in both) using cultivation methods, taxon-specific polymerase chain reactions (PCRs), multiplex PCRs and next-generation amplicon sequencing. Mainly members of the natural microbial community of the well waters and bacteria originating from the environment were detected but several opportunistic pathogenic taxa, e.g., Pseudomonas aeruginosa, P. stutzeri, Acinetobacter johnsoni, Acinetobacter baumanni, Moraxella osloensis, Microbacterium paraoxydans, Legionella spp., Stenotrophomonas maltophilia and Staphylococcus aureus were revealed by the applied methods. Pools with charging-unloading operation had higher microscopic cell counts, colony-forming unit (CFU) counts, number of cocci, P. aeruginosa and S. aureus compared to the recirculation systems. Bacteria originating from human sources (e.g., skin) were identified in the pool waters with less than 1% relative abundance, and their presence was sporadic in the pools. Comparing the microbiological quality of the pools based on the first sampling time and the following four months' period it was revealed that recirculation operation type has better water quality than the charging-unloading pool operation from a hygienic point of view.

Siculibacillus lacustris gen. nov., sp. nov., a new rosette-forming bacterium isolated from a freshwater crater lake (Lake St. Ana, Romania).

A new aerobic alphaproteobacterium, strain SA-279T, was isolated from a water sample of a crater lake. The 16S rRNA gene sequence analysis revealed that strain SA-279T formed a distinct lineage within the family Ancalomicrobiaceae and shared the highest pairwise similarity values with Pinisolibacterravus E9T (96.4 %) and Ancalomicrobiumadetum NBRC 102456T (94.2 %). Cells of strain SA-279T were rod-shaped, motile, oxidase and catalase positive, and capable of forming rosettes. Its predominant fatty acids were C18 : 1ω7c (69.0 %) and C16 : 1ω7c (22.7 %), the major respiratory quinone was Q-10, and the main polar lipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, an unidentified aminophospholipid and an unidentified lipid. The G+C content of the genomic DNA of strain SA-279T was 69.2 mol%. On the basis of the phenotypic, chemotaxonomic and molecular data, strain SA-279T is considered to represent a new genus and species within the family Ancalomicrobiaceae, for which the name Siculibacillus lacustris gen. nov., sp. nov. is proposed. The type strain is SA-279T (=DSM 29840T=JCM 31761T).

Deinococcus fonticola sp. nov., isolated from a radioactive thermal spring in Hungary.

A Gram-stain-negative, aerobic, non-motile and coccus-shaped bacterium, designated strain FeSDHB5-19T, was isolated from a biofilm sample collected from a radioactive thermal spring (Budapest, Hungary), after exposure to 5 kGy gamma radiation. A polyphasic approach was used to study the taxonomic properties of strain FeSDHB5-19T, which had highest 16S rRNA gene sequence similarity to Deinococcus antarcticus G3-6-20T (96.5 %). The 16S rRNA gene sequence similarity to type strains of other Deinococcus species were 93.0 % or lower. The DNA G+C content of the draft genome sequence, consisting of 3.9 Mb, was 63.9 mol%. Strain FeSHDB5-19T was found to grow at temperatures of 10-32 °C (optimum, 28 °C) and pH 5-10 (pH 6.5-7.5) and tolerated up to 1.5 % NaCl (w/v) with optimum growth at 0-0.5 % NaCl. The predominant fatty acids (>10 %) were C16 : 0 and C16 : 1ω7c. The cell-wall peptidoglycan type was A3ß l-Orn-Gly1-2. The whole-cell sugars were glucose and low amounts of galactose. Strain FeSDHB5-19T possessed MK-8 as the predominant respiratory quinone, typical of the genus Deinococcus. The polar lipid profile contained unidentified phosphoglycolipids and unidentified glycolipids. The isolate was found to be highly resistant to gamma (D10<8 kGy) and UV (D10~800 J m-2) radiation. According to its genotypic, phenotypic and chemotaxonomic characteristics, strain FeSDHB5-19T represents a novel species in the genus Deinococcus, for which the name Deinococcusfonticola sp. nov. is proposed. The type strain is FeSDHB5-19T (=NCAIM B.02639T=DSM 106917T).

Dual bloom of green algae and purple bacteria in an extremely shallow soda pan.

In April 2014, dual bloom of green algae and purple bacteria occurred in a shallow, alkaline soda pan (Kiskunság National Park, Hungary). The water was only 5 cm deep, in which an upper green layer was clearly separated from a near-sediment purple one. Based on microscopy and DNA-based identification, the upper was inhabited by a dense population of the planktonic green alga, Oocystis submarina Lagerheim, while the deeper layer was formed by purple, bacteriochlorophyll-containing bacteria, predominated by Thiorhodospira and Rhodobaca. Additional bacterial taxa with a presumed capability of anoxygenic phototrophic growth belonged to the genera Loktanella and Porphyrobacter. Comparing the bacterial community of the purple layer with a former blooming event in a nearby soda pan, similar functional but different taxonomic composition was revealed. Members from many dominant bacterial groups were successfully cultivated including potentially new species, which could be the result of the application of newly designed media.

The actinobacterium Tsukamurella paurometabola has a functionally divergent arylamine N-acetyltransferase (NAT) homolog.

Actinobacteria in the Tsukamurella genus are aerobic, high-GC, Gram-positive mycolata, considered as opportunistic pathogens and isolated from various environmental sources, including sites contaminated with oil, urban or industrial waste and pesticides. Although studies look into xenobiotic biotransformation by Tsukamurella isolates, the relevant enzymes remain uncharacterized. We investigated the arylamine N-acetyltransferase (NAT) enzyme family, known for its role in the xenobiotic metabolism of prokaryotes and eukaryotes. Xenobiotic sensitivity of Tsukamurella paurometabola type strain DSM 20162T was assessed, followed by cloning, recombinant expression and functional characterization of its single NAT homolog (TSUPD)NAT1. The bacterium appeared quite robust against chloroanilines, but more sensitive to 4-anisidine and 2-aminophenol. However, metabolic activity was not evident towards those compounds, presumably due to mechanisms protecting cells from xenobiotic entry. Of the pharmaceutical arylhydrazines tested, hydralazine was toxic, but the bacterium was less sensitive to isoniazid, a drug targeting mycolic acid biosynthesis in mycobacteria. Although (TSUPD)NAT1 protein has an atypical Cys-His-Glu (instead of the expected Cys-His-Asp) catalytic triad, it is enzymatically active, suggesting that this deviation is likely due to evolutionary adaptation potentially serving a different function. The protein was indeed found to use malonyl-CoA, instead of the archetypal acetyl-CoA, as its preferred donor substrate. Malonyl-CoA is important for microbial biosynthesis of fatty acids (including mycolic acids) and polyketide chains, and the corresponding enzymatic systems have common evolutionary histories, also linked to xenobiotic metabolism. This study adds to accummulating evidence suggesting broad phylogenetic and functional divergence of microbial NAT enzymes that goes beyond xenobiotic metabolism and merits investigation.

Changes in bacterial and archaeal communities during the concentration of brine at the graduation towers in Ciechocinek spa (Poland).

This study evaluates the changes in bacterial and archaeal community structure during the gradual evaporation of water from the brine (extracted from subsurface Jurassic deposits) in the system of graduation towers located in Ciechocinek spa, Poland. The communities were assessed with 16S rRNA gene sequencing (MiSeq, Illumina) and microscopic methods. The microbial cell density determined by direct cell count was at the order of magnitude of 107 cells/mL. It was found that increasing salt concentration was positively correlated with both the cell counts, and species-level diversity of bacterial and archaeal communities. The archaeal community was mostly constituted by members of the phylum Euryarchaeota, class Halobacteria and was dominated by Halorubrum-related sequences. The bacterial community was more diverse, with representatives of the phyla Proteobacteria and Bacteroidetes as the most abundant. The proportion of Proteobacteria decreased with increasing salt concentration, while the proportion of Bacteroidetes increased significantly in the more concentrated samples. Representatives of the genera Idiomarina, Psychroflexus, Roseovarius, and Marinobacter appeared to be tolerant to changes of salinity. During the brine concentration, the relative abundances of Sphingobium and Sphingomonas were significantly decreased and the raised contributions of genera Fabibacter and Fodinibius were observed. The high proportion of novel (not identified at 97% similarity level) bacterial reads (up to 42%) in the 16S rRNA gene sequences indicated that potentially new bacterial taxa inhabit this unique environment.

A new Rhizobium species isolated from the water of a crater lake, description of Rhizobium aquaticum sp. nov.

A novel isolate, strain SA-276T, was isolated from the water of Lake St. Ana, a crater lake which is located in Romania. Phylogenetic analysis based on the 16S rRNA gene revealed that the new strain is a member of the family Rhizobiaceae, showing a high pairwise similarity value (97.65%) to Rhizobium tubonense CCBAU 85046T (= DSM 25379T), Rhizobium leguminosarum USDA 2370T (= LMG 14904T), Rhizobium anhuiense CCBAU 23252T and Rhizobium laguerreae FB206T. Cells of strain SA-276T were rod-shaped, motile, oxidase negative and weakly catalase positive. The predominant fatty acids were C18:1ω7c and cyclo C19:0ω8c, the major respiratory quinones were Q-10 and Q-9, and the main polar lipids were phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine. The G + C content of the genomic DNA of strain SA-276T was 60.8 mol%. The novel isolate can be distinguished from the closest related type strain R. tubonense DSM 25379T based on its broader substrate specificity and positive trypsin enzyme activity. On the basis of the phenotypic, chemotaxonomic and molecular data, strain SA-276T is considered to represent a new species, for which the name Rhizobium aquaticum sp. nov. is proposed. The type strain is SA-276T (= DSM 29780T = JCM 31760T).

Microbial community changes during a toxic cyanobacterial bloom in an alkaline Hungarian lake.

The Carpathian Basin is a lowland plain located mainly in Hungary. Due to the nature of the bedrock, alluvial deposits, and a bowl shape, many lakes and ponds of the area are characterized by high alkalinity. In this study, we characterized temporal changes in eukaryal and bacterial community dynamics with high throughput sequencing and relate the changes to environmental conditions in Lake Velence located in Fejér county, Hungary. The sampled Lake Velence microbial populations (algal and bacterial) were analyzed to identify potential correlations with other community members and environmental parameters at six timepoints over 6 weeks in the Spring of 2012. Correlations between community members suggest a positive relationship between certain algal and bacterial populations (e.g. Chlamydomondaceae with Actinobacteria and Acidobacteria), while other correlations allude to changes in these relationships over time. During the study, high nitrogen availability may have favored non-nitrogen fixing cyanobacteria, such as the toxin-producing Microcystis aeruginosa, and the eutrophic effect may have been exacerbated by high phosphorus availability as well as the high calcium and magnesium content of the Carpathian Basin bedrock, potentially fostering exopolymer production and cell aggregation. Cyanobacterial bloom formation could have a negative environmental impact on other community members and potentially affect overall water quality as well as recreational activities. To our knowledge, this is the first prediction for relationships between photoautotrophic eukaryotes and bacteria from an alkaline, Hungarian lake.

Alkaline and Halophilic Protease Production by Bacillus luteus H11 and Its Potential Industrial Applications.

This paper presents the results of the study on the production of protease by Bacillus luteus H11 isolated from an alkaline soda lime. B. luteus H11 was identified as an alkalohalophilic bacterium, and its extracellular serine endoprotease also showed an extreme alkali- and halotolerance. It was remarkably stable in the presence of NaCl up to 5 M. The enzyme was active in a broad range of pH values and temperatures, with an optimum pH of 10.5 and a temperature of 45 °C. It had a molecular mass of about 37 kDa and showed activity against azocasein and a synthetic substrate for the subtilisin-like protease, N-succinyl-l-phenylalanine-p-nitroanilide. The halo-alkaline protease produced by B. luteus H11 seems to be significant from an industrial perspective because of its tolerance towards high salinity and alkalinity as well as its stability against some organic solvents, surfactants and oxidants. These properties make the protease suitable for applications in food, detergent and pharmaceutical industries, and also in environmental bioremediation.

The effect of reconstruction works on planktonic bacterial diversity of a unique thermal lake revealed by cultivation, molecular cloning and next generation sequencing.

The aim of this study was to gain detailed information about the diversity of planktonic bacterial communities of a worldwide special peat bedded natural thermal spa lake, and to reveal the effect of a lake wall reconstruction work. To compare the efficiency of different methods used for analyzing bacterial diversity, cultivation, molecular cloning and pyrosequencing were applied simultaneously. Despite the almost unchanged physical-chemical parameters and cell count values of lake water, remarkable differences were observed in the planktonic bacterial community structures during and after the reconstruction by all applied microbiological approaches. Rhodobacter sp. was found to be one of the most abundant community members during the works probably due to the sediment stirring effect of the reconstruction. Following the reconstruction higher diversity was detected than during the works by all approaches. Bacterial strains related to species Chryseobacterium and Exiguobacterium, furthermore sequences related to Arcobacter, Gemmobacter and MWH-UniP1 aquatic group were identified in the highest proportion at that time. Although the differences revealed by cultivation based and independent community structures were significant, only minor disparities were found by molecular cloning and next generation sequencing techniques.

Caenimicrobium hargitense gen. nov., sp. nov., a new member of the family Alcaligenaceae (Betaproteobacteria) isolated from activated sludge.

A new betaproteobacterium, CGII-59m2T, was isolated from an activated sludge bioreactor which treated landfill leachate. The 16S rRNA gene sequence analysis revealed that strain CGII-59m2T belonged to the family Alcaligenaceae and shared the highest pairwise similarity values with Parapusillimonas granuli LMG 24012T (97.7 %), various species of the genus Bordetella (97.3-97.0 %) and Candidimonas nitroreducens LMG 24812T (97.0 %). Cells of strain CGII-59m2T were rod-shaped, non-motile, and oxidase- and catalase-positive. The predominant fatty acids were C16 : 1ω7c, C16 : 0, cyclo C17 : 0 and C18 : 1ω7c, the major respiratory quinone was Q-8, and the main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unknown phospholipid. The G+C content of the genomic DNA of strain CGII-59m2T was 62.3 mol%. The new bacterium can be distinguished from the closely related type strains based on its non-motile cells and its high C16 : 1ω7c fatty acid content. On the basis of the phenotypic, chemotaxonomic and molecular data, strain CGII-59m2T is considered to represent a novel species of a new genus, for which the name Caenimicrobium hargitense gen. nov., sp. nov. is proposed. The type strain is CGII-59m2T (=DSM 29806T=NCAIM B.02615T).

Nitrincola alkalilacustris sp. nov. and Nitrincola schmidtii sp. nov., alkaliphilic bacteria isolated from soda pans, and emended description of the genus Nitrincola.

Three alkaliphilic and halotolerant bacterial strains, designated ZV-19T, R4-8T and S4-12, were isolated from the water of soda pans located in the Kiskunság National Park, Hungary. Cells of all three strains were Gram-staining-negative, rod-shaped, motile and non-endospore-forming. They were facultatively anaerobic, and oxidase- and catalase-positive. Their major isoprenoid quinone was Q-8, and their predominant fatty acids were C18 : 1ω7c, C16 : 1ω7c and C16 : 0. The DNA G+C content was 54.5 mol% in strain ZV-19 T and 45.8 mol% in strain R4-8T. The 16S rRNA gene based phylogenetic analysis showed that all three strains were members of the genus Nitrincola (family Oceanospirillaceae, class Gammaproteobacteria). Strain ZV-19T showed 96.6 and 95.5 % sequence similarities and 19±3 and 18±3 % DNA-DNA relatedness to Nitrincolalacisaponensis DSM 16316T and Nitrincolaalkalisediminis JCM 19317T, respectively. Strains R4-8T and S4-12 exhibited 97.9 and 98.6 % sequence matches and 34±4 and 13±8 % DNA-DNA hybridization values with N. lacisaponensis DSM 16316T and N. alkalisediminis JCM 19317T, respectively. According to the phenotypic, chemotaxonomic and phylogenetic data, the strains studied represent two novel species, Nitrincola alkalilacustris sp. nov. with the type strain ZV-19T (=DSM 29817T=NCAIM B 02612T) and Nitrincola schmidtii sp. nov. with the type strain R4-8T (=DSM 100788T=NCAIM B.02626T). An emended description of the genus Nitrincola is also presented.

Quisquiliibacterium transsilvanicum gen. nov., sp. nov., a novel betaproteobacterium isolated from a waste-treating bioreactor.

A new betaproteobacterium, CGI-09T, was isolated from an activated sludge bioreactor which treated landfill leachate. Based on 16S rRNA gene sequence analysis, the new strain shared the highest pairwise similarity values with members of the order Burkholderiales: Derxia gummosa IAM 13946T (family Alcaligenaceae), 93.7 % and Lautropia mirabilis DSM 11362T (family Burkholderiaceae), 93.6 %. Cells of strain CGI-09T were rod-shaped and non-motile. The new strain was oxidase and catalase positive and capable of reducing nitrate to nitrite. The predominant fatty acids were C16 : 1 ω7c, C16 : 0, cycloC17 : 0 and C18 : 1 ω7c, the major respiratory quinone was Q-8, and the detected polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unknown phospholipid. The G+C content of the genomic DNA of strain CGI-09T was 70.2 mol%. The new bacterium can be distinguished from the members of genera Derxia and Lautropia based on its non-motile cells, arginine dihydrolase activity, its high cyclo C17 : 0 fatty acid content and the lack of hydroxy fatty acids. On the basis of the phenotypic, chemotaxonomic and molecular data, strain CGI-09T is considered to represent a new genus and species within the family Burkholderiaceae, for which the name Quisquiliibacterium transsilvanicum gen. nov., sp. nov. is proposed. The type strain is CGI-09T (=DSM 29781T=JCM 31785T).

Rhodococcus sovatensis sp. nov., an actinomycete isolated from the hypersaline and heliothermal Lake Ursu.

A Gram-stain-positive, strictly aerobic, mesophilic bacterium, designated H004T, was isolated from a water sample of the hypersaline and heliothermal Lake Ursu, Sovata, Romania. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain H004T formed a distinct phyletic lineage within the genus Rhodococcus. It shared the highest 16S rRNA gene sequence similarity with Rhodococcus yunnanensis YIM 70056T (98.80 %), followed by Rhodococcus fascians LMG 3623T (98.73 %), Rhodococcus cercidiphylli YIM 65003T (98.73 %), Rhodococcus cerastii C5T (98.58 %) and Rhodococcus kyotonensis DS472T (98.53 %). The alkB-based phylogenetic analysis further confirmed that this strain constitutes a highly unique lineage within the genus. Chemotaxonomic characteristics, including the predominant fatty acids acids C15 : 0, C18 : 1ω9c, C19 : 1ω11c/C19 : 1ω9c and C16 : 1ω7c/iso-C15 : 0 2-OH, the major quinone MK-8(H2), the presence of mycolic acids and cell-wall chemotype IV were also consistent with the properties of members of the genus Rhodococcus. The DNA G+C content of strain H004T was 65.4 mol%. The results of DNA-DNA hybridization analyses with the closest relatives, in combination with the alkB-based phylogenetic analysis, as well as the chemotaxonomic and physiological data, demonstrated that isolate H004T represents a novel species of the genus Rhodococcus, for which the name Rhodococcus sovatensissp. nov. is proposed. The type strain is H004T (=DSM 102881T=NCAIM B.02632T).

Soda pans of the Pannonian steppe harbor unique bacterial communities adapted to multiple extreme conditions.

Soda pans of the Pannonian steppe are unique environments regarding their physical and chemical characteristics: shallowness, high turbidity, intermittent character, alkaline pH, polyhumic organic carbon concentration, hypertrophic condition, moderately high salinity, sodium and carbonate ion dominance. The pans are highly productive environments with picophytoplankton predominance. Little is known about the planktonic bacterial communities inhabiting these aquatic habitats; therefore, amplicon sequencing and shotgun metagenomics were applied to reveal their composition and functional properties. Results showed a taxonomically complex bacterial community which was distinct from other soda lakes regarding its composition, e.g. the dominance of class Alphaproteobacteria was observed within phylum Proteobacteria. The shotgun metagenomic analysis revealed several functional gene components related to the harsh and at the same time hypertrophic environmental conditions, e.g. proteins involved in stress response, transport and hydrolase systems targeting phytoplankton-derived organic matter. This is the first detailed report on the indigenous planktonic bacterial communities coping with the multiple extreme conditions present in the unique soda pans of the Pannonian steppe.