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Összefoglalás. A kibányászható foszfátércek fogyóban vannak. A nemzetközi kutatások alapján a felmerülő foszfáthiány enyhítésére megoldást jelenthet a szennyvíztelepeken spontán képződő, és ott üzemeltetési problémát is okozó foszfátásványok hasznosítása. A vizsgált szennyvíztisztítóban két foszfátásvány, a struvit ([NH4]Mg[PO4]·6H2Orombos) és a vivianit (Fe3(PO4)2·8H2Omonoklin) okoz problémát. A technológiai folyamatban azonosítottuk azt az egyik pontot, ahol ma – szándékolatlanul – szubmikrométeres vivianitkristályok nukleációja történhet. E ponton beavatkozva, vagy e pont után egy új műtárggyal tudatosan erősítve a kristályképződést mind a nyersanyag-leválasztás, mind az üzemeltetési probléma csökkentése lehetővé válhat. Summary. Based on the experience of the past decades, the 21th century is challenged with several environmental problems that call for a solution at a global level. One such problem of the foreseeable future is, according to scientific forecasts, the shortage in phosphate rocks. Phosphate minerals forming spontaneously in sewage plants and causing operational difficulties at the same time, with a proper technological design can alleviate the emerging problem of phosphate shortage. We examined the phosphate mineral precipitation processes in a large-capacity sewage treatment plant in Hungary. Both the precipitated phases and phosphorus content characteristics of the sewage sludge were studied. X-ray powder diffraction (XPD) was used to identify the minerals. The total phosphorus content (expressed as phosphate concentration) and the dissolved orthophosphate content of the sewage sludge samples were measured by molybdenate spectrophotometric method. Our findings point to two main phosphate minerals: struvite (Mg(NH4)[PO4] · 6H2Oorthorhombic) and vivianite (Fe3[PO4]2 · 8H2Omonoclinic) formed as technologically harmful precipitates at the sewage plant (Figure 1). The two minerals occur downstream of the digester, at separate, well-defined points of the technological line (Figure 2). Both crystalline compounds are potentially suitable for the alleviation of the impending global phosphate shortage. We determined the total P content (expressed as phosphate concentration) of sewage sludge samples, along with the quantitative distribution of the dissolved (liquid; orthophosphate) and solid (organic phosphate, polyphosphate, phosphate minerals) fractions of the sludge prior and after the anaerobic digester tanks (Figure 3). The total P content (expressed as phosphate concentration) – in full agreement with the expectations – has practically not changed during digestion (Figure 3; columns # K1 MW vs. 5 MW). Concerning the P forms present in the sludge we expected an increase of dissolved orthophosphate at the expense of bonded phosphate after the digestion (Figure 3; column # „elméleti”); however the actual orthophosphate content dropped by 80% in the sample after the digester (Figure 3; columns # K1 vs. 5). The misfit between the stable total P content and the decreasing amount of both the dissolved (ortho)phosphate and solid polyphosphate in the digester clearly indicates the formation of submicroscopic vivianite, confirming from the P speciation side the findings of Wilfert et al. (2018). That process is triggered by the addition of FeCl3 into the digester. The more controlled FeCl3 treatment and/or a new technological step (mineral separator tank) included right after the digester may help the separation of up to 50% or more of phosphorous from the sludge in the form of vivianite. By that step the spontaneous and harmful mineral formation, currently visible on the technological equipment following the digestion, could also be reduced significantly.

Soil organic matter (SOM) is an essential fraction of soil and contributes to its fertility. Land use and cultivation may affect SOM. This study investigates whether SOM concentration and composition differ in soil pools or are changed by soil management (tillage, fertilisations, and crop covers). Soil samples were collected in April 2019 from cropland and nearby grassland. The study sites were part of a long-term experiment in Martonvasar (Hungary), established in 1958 and characterised by Chernozem soils. Total organic carbon (TOC) contents and compounds were studied in three soil pools (bulk soil, fast pool, and slow pool). Both TOC and total N concentrations were high in the slow pool, with higher stored C contents in grassland than in cropland. Tillage effects reduced aggregate stability in cropland, which explains a lower aliphatic content than grassland. Insufficient physical protection due to the tillage practice may enhance OM loss in cropland even under fertiliser inputs. Neither fertiliser nor crop covers affected SOM compositions, while they were different in soil pools. More complex OM in the slow pool than in the fast pool. It indicates that the slow pool is the main protecting path for SOM, possibly referred to older or decayed organic compounds. To understand the bottom-up process, microorganisms’ community role in SOM stabilisation needs to be studied.

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).

Bacteria employ secondary metabolism to combat competitors, and xenobiotic metabolism to survive their chemical environment. This project has aimed to introduce a bacterial collection enabling comprehensive comparative investigations of those functions. The collection comprises 120 strains (Proteobacteria, Actinobacteria and Firmicutes), and was compiled on the basis of the broad taxonomic range of isolates and their postulated biosynthetic and/or xenobiotic detoxification capabilities. The utility of the collection was demonstrated in two ways: first, by performing 5144 co-cultures, recording inhibition between isolates and employing bioinformatics to predict biosynthetic gene clusters in sequenced genomes of species; second, by screening for xenobiotic sensitivity of isolates against 2-benzoxazolinone and 2-aminophenol. The co-culture medium of Bacillus siamensis D9 and Lysinibacillus sphaericus DSM 28T was further analysed for possible antimicrobial compounds, using liquid chromatography-mass spectrometry (LC-MS), and guided by computational predictions and the literature. Finally, LC-MS analysis demonstrated N-acetylation of 3,4-dichloroaniline (a toxic pesticide residue of concern) by the actinobacterium Tsukamurella paurometabola DSM 20162T which is highly tolerant of the xenobiotic. Microbial collections enable "pipeline" comparative screening of strains: on the one hand, bacterial co-culture is a promising approach for antibiotic discovery; on the other hand, bioremediation is effective in combating pollution, but requires knowledge of microbial xenobiotic metabolism. The presented outcomes are anticipated to pave the way for studies that may identify bacterial strains and/or metabolites of merit in biotechnological applications.

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.

There is an increasing interest in studying bacterial-fungal interactions (BFIs), also the interactions of Pleurotus ostreatus, a model white-rot fungus and important cultivated mushroom. In Europe, P. ostreatus is produced on a wheat straw-based substrate with a characteristic bacterial community, where P. ostreatus is exposed to the microbiome during substrate colonisation. This study investigated how the bacterial community structure was affected by the introduction of P. ostreatus into the mature substrate. Based on the results obtained, the effect of the presence and absence of this microbiome on P. ostreatus production in an experimental cultivation setup was determined. 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and amplicon sequencing revealed a definite succession of the microbiome during substrate colonisation and fruiting body production: a sharp decrease in relative abundance of Thermus spp. and Actinobacteria, and the increasing dominance of Bacillales and Halomonas spp. The introduced experimental cultivation setup proved the protective role of the microbial community against competing fungi without affecting P. ostreatus growth. We could also demonstrate that this effect could be attributed to both living microbes and their secreted metabolites. These findings highlight the importance of bacterial-fungal interactions during mushroom production., Bacterial community composition has changed significantly during Pleurotus ostreatus production, and this microbiome has a role in inhibiting competing microbes without affecting P. ostreatus growth.

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.

The thermal waters of Gellert Hill discharge area of the Buda Thermal Karst System (Hungary) are characterized by high (up to 1000 Bq/L) 222Rn-activity due to the radium-accumulating biogeochemical layers. Samples were taken from these ferruginous and calcareous layers developed on spring cave walls and water surface. Accumulation of potentially toxic metals (e.g. As, Hg, Pb, Sn, Sr, Zn) in the dense extracellular polymeric substance containing bacterial cells and remains was detected by inductively coupled plasma mass spectrometry. The comparison of bacterial phylogenetic diversity of the biofilm samples was performed by high throughput next generation sequencing (NGS). The analysis showed similar sets of mainly unidentified taxa of phyla Chloroflexi, Nitrospirae, Proteobacteria, Planctomycetes; however, large differences were found in their abundance. Cultivation-based method complemented with irradiation assay was performed using 5, 10 and 15 kGy doses of gamma-rays from a 60Co-source to reveal the extreme radiation-resistant bacteria. The phyla Actinobacteria, Firmicutes, Proteobacteria (classes Alpha- Beta- and Gammaproteobacteria), Bacteriodetes and Deinococcus-Thermus were represented among the 452 bacterial strains. The applied irradiation treatments promoted the isolation of 100 different species, involving candidate novel species, as well. The vast majority of the isolates belonged to bacterial taxa previously unknown as radiation-resistant microorganisms. Members of the genera Paracoccus, Marmoricola, Dermacoccus and Kytococcus were identified from the 15 kGy dose irradiated samples. The close relatives of several known radiation-tolerant bacteria were also detected from the biofilm samples, alongside with bacteria capable of detoxification by metal accumulation, adsorption and precipitation in the form of calcium-carbonate which possibly maintain the viability of the habitat. The results suggest the establishment of a unique, extremophilic microbiota in the studied hydrothermal spring caves.

Plant Growth Promoting Rhizobacteria (PGPR) are commonly applied in agricultural systems as biofertilizers due to their beneficial effects on plant productivity and crop yield. Considering the growing nutritional needs of the human population, PGPR inoculants adapted to deteriorated soil conditions offer a sustainable way for crop production. The objective of this study was to detect the presence and estimate the relative abundance of the PGPR members of ‘stress-tolerant’ bacterial inocula, and to investigate their effect on the indigenous bacterial community structure of the maize rhizosphere. The acid stress tolerant bacterial inocula were compared to inocula used in mildly alkaline soil, during the 112-day growth period of maize. The Terminal Restriction Fragment Length Polymorphism (T-RFLP) molecular fingerprint method offered a possibility for monitoring the applied bacteria. Two different restriction endonucleases were selected in silico and tested in vitro for specific detection of the inoculated PGPR. The developed T-RFLP model system indicated a clear positive effect of inoculants on the relative abundance of Azospirillum species in mildly alkaline (pH 7.3) and acid (pH 5.35) plot between days 14 and 21, and also on that of Agreia pratensis in acid plot in the period between days 35 and 56. In case of Azospirillum and acid soil the positive effect proved to be statistically significant (2–5 times higher relative abundances compared to the control). Similarly, the abundances of the monitored PGPR species and the maize yield were more positively influenced in acid soil than in mildly alkaline soil treated by the inocula developed. In the case of acid soil treatments resulted in significant growth of cob number (1.29–1.44 times of the control). The bacterial community structure of the rhizosphere significantly differed depending on soil type and maize growth stage.

E tanulmány célja egy martonvásári hosszútávú tartamkísérlet trágyázás nélkül művelt kukorica monokultúra talajában fellelhető baktériumközösségek filogenetikai diverzitásának és anyagcsere potenciáljának a felmérése volt. A kutatás során NGS és MicroResp™ technikával vizsgáltuk a művelt és a természeteshez közeli állapotú talajok mikrobiális jellemzőit.Az NGS adatai alapján a kukorica monokultúra szántott rétegének mintáinak baktériumközösség szerkezete nagyfokú hasonlóságot mutatott egymással, és elkülönült a löszpusztagyep A és C rétegéből formálódó csoporttól, míg a kukorica monokultúra C szintjéből származó minta élesen elvált a többitől. A gyepek talajában nem találtunk nagyobb bakteriális taxonómiai diverzitást, mint a művelt talajokban.A MicroResp™ mérés alapján megállapítottuk, hogy a természeteshez közeli állapotú talajok felszínhez közeli (A) rétegében kiugró a mikrobiális aktivitás mértéke. A kukorica monokultúrából származó A szint minták mikrobiális aktivitási mintázata egymáshoz hasonló volt, a C rétegből származó minták külön csoportot képeztek.Eredményeink alapján tehát a hosszú távú tartamkísérletbe vont művelt talajok baktériumközösségeinek filogenetikai diverzitása és metabolikus potenciálja jelentősen eltért a löszpusztagyep mintákétól.

Understanding the effect of different agricultural practices on soil microbiome is very important since it has a decisive role in the multifunctionality of soils. Our research aimed to reveal and compare the changes in the composition of soil bacterial and archaeal communities in response to cultivation and fertilization regimes. Soil samples were collected from a long-term (60-year-old) field experiment with maize (Zea mays L.) monoculture under inorganic fertilization, combined fertilization (inorganic and farmyard manure) and without fertilization, and a nearby fallow land five times over a crop cycle. The bacterial and archaeal community compositions were revealed by amplicon sequencing of the 16S rRNA genes on Illumina MiSeq platform. Significant differences were observed between cultivated soils and fallow land, as well as among cultivated soils under different fertilization regimes in both bacterial and archaeal community structures. Many taxa (e.g. Gaiella, Burkholderiaceae, Saprospiraceae, Rhodoplanes, MB-A2-108 and Cand. Nitrososphaera) were found to be more abundant in the fallow land than in the cultivated soils. The exclusive use of inorganic fertilizer resulted in a significantly different bacterial and archaeal community structure with higher relative abundance of sequences affiliated with mostly acidotolerant taxa (e.g. Bryobacter, Cand. Solibacter, Acidibacteriales, WPS-2 and Cand. Nitrosotalea). These taxa were not enriched in the combined fertilizer treatment, even though the manure was applied only once every four years. The results demonstrated a strong effect of inorganic fertilizers on the soil bacterial and archaeal communities, however, these effects can be decreased by the application of farmyard manure.

Astatic soda pans of the Pannonian Steppe are unique environments with respect to their multiple extreme physical and chemical characteristics (high daily water temperature fluctuation, high turbidity, alkaline pH, salinity, polyhumic organic carbon concentration, hypertrophic state and special ionic composition). However, little is known about the seasonal dynamics of the bacterial communities inhabiting these lakes and the role of environmental factors that have the main impact on their structure. Therefore, two soda pans were sampled monthly between April 2013 and July 2014 to reveal changes in the planktonic community. By late spring in both years, a sudden shift in the community structure was observed, the previous algae-associated bacterial communities had collapsed, resulting the highest ratio of Actinobacteria within the bacterioplankton (89%, with the dominance of acIII-A1 lineage) ever reported in the literature. Before these peaks, an extremely high abundance (> 10,000 individuum l−1) of microcrustaceans (Moina brachiata and Arctodiaptomus spinosus) was observed. OTU-based statistical approaches showed that in addition to algal blooms and water-level fluctuations, zooplankton densities had the strongest effect on the composition of bacterial communities. In these extreme environments, this implies a surprisingly strong, community-shaping top-down role of microcrustacean grazers.

Little is known about the detailed community composition of heterotrophic bacterioplankton in macrophyte-dominated littoral systems, where a considerable amount of dissolved organic carbon originates from aquatic macrophytes instead of phytoplankton. The aim of the present study was to reveal the effect of macrophytes on the microbial community and to elucidate their role in a macrophyte-dominated shallow soda lake, which can be characterised by a mosaic of open waters and reed marsh. Therefore, 16S rRNA gene amplicon sequencing, the most probable number method, cultivation of bacterial strains, EcoPlate and cultivation-based substrate utilisation techniques were applied. Differences in the structures of microbial communities were detected between the water and the sediment samples and between vegetated and unvegetated water samples. Planktonic bacterial communities of an inner pond and a reed-covered area showed significant similarities to each other. Woesearchaeia was the dominant archaeal taxon in the water samples, while Bathyarchaeia, ‘Marine Benthic Group D' and 'DHVEG-1’ were abundant in the sediment samples. The most probable number of heterotrophic bacteria was lower in the open water than in the reed-associated areas. The vast majority (83%) of the isolated bacterial strains from the water samples of the reed-covered area were able to grow on a medium containing reed extract as the sole source of carbon.

The top metre of the soil is one of the largest terrestrial carbon reservoirs. More than 50% of the soil carbon is stored as soil organic matter (SOM). Several papers report about the SOM losses due to tillage and land-use change. On the other hand, a huge amount of papers focus on the environmental potential of various min-till, no-till and other techniques for regenerative agriculture. The change of the fertilization regime also has an influence on SOM so it also can influence the humus status of the soils. This presentation focuses on the effects of different kinds of fertilization and abandonment of arable lands on the quantity and quality of the SOM.The present study is based on Martonvásár Experimental Station (Hungary) which was established in 1958. The research focused on maize monoculture with the following treatments: (a) no fertilization, (b) NPK, (c) NPK with manure addition. The soil of the plots is Chernozem. Two controls were selected: (a) a natural Grassland and a secondary grassland. The secondary grassland was an arable land until 1990. Five repetitions of soil samples were taken from each plot and times. Soils were fractionated to silt and clay associated OM (s+c), aggregate associated OM (S+A), dissolved organic matter (DOM) and particulate organic matter (POM) according to Zimmermann’s method (4). Quality parameters of the DOM were studied by CN analyser, UV-Vis spectrometer, spectrofluorometer, zetasizer and size exclusion chromatograph. Solid SOM fractions were studied by CHNS analyser, ATR-FTIR and DRIFT FTIR. The V3-V4 regions of the 16S rRNA gene obtained from the soil samples were sequenced on the Illuma platform for the description of microbial diversity.Twenty years were enough to restore the natural SOM content of the soils (land-use change from arable land to grassland). Labile fractions of the SOM were higher in case of secondary than the primary grasslands. We have found differences in weight ratios of SOM fractions between fertilization regimes, as well. The proportion of microbial contribution to SOM were higher in the arable soils than the grasslands based on the C:N ratios of the SOM. However, the predominance of phyla Proteobacteria, Acidobacteria, Bacteriodetes, Actinobacteria and Verrucomicrobia in all studied soils, microbial diversity is generally higher in the grasslands than in the arable plots. The DOM of different fertilization regimes and land uses have shown the most characteristic differences. The difference between arable plots (with various fertilization regimes) and grasslands can be characterized by humic substances (HS) with higher condensation degree and molecular mass. The application of manure has result same proportion of peptide-like components and HS with lower molecular as the DOM of grassland soils.The microbial diversity of abandoned arable land remained similar to that of the arable lands over twenty years. The major part of the growth of SOM occurred in the labile fractions. The change of the fertilization regime also has limited potential to grow a total mass of SOM.Support of the GINOP 2.3.2-15-2016-00056 and National Research, Development and Innovation Office under contracts K123953 are gratefully acknowledged.

Short-chain halogenated aliphatic hydrocarbons (e.g. perchloroethene, trichloroethene) are among the most toxic environmental pollutants. Perchloroethene and trichloroethene can be dechlorinated to non-toxic ethene through reductive dechlorination by Dehalococcoides sp. Bioaugmentation, applying cultures containing organohalide-respiring microorganisms, is a possible technique to remediate sites contaminated with chlorinated ethenes. Application of site specific inocula is an efficient alternative solution. Our aim was to develop site specific dechlorinating microbial inocula by enriching microbial consortia from groundwater contaminated with trichloroethene using microcosm experiments containing clay mineral as solid phase. Our main goal was to develop fast and reliable method to produce large amount (100 L) of bioactive agent with anaerobic fermentation technology. Polyphasic approach has been applied to monitor the effectiveness of dechlorination during the transfer process from bench-scale (500 mL) to industrial-scale (100 L). Gas chromatography measurement and T-RFLP (Terminal Restriction Fragment Length Polymorphism) revealed that the serial subculture of the enrichments shortened the time-course of the complete dechlorination of trichloroethene to ethene and altered the composition of bacterial communities. Complete dechlorination was observed in enrichments with significant abundance of Dehalococcoides sp. cultivated at 8 °C. Consortia incubated in fermenters at 18 °C accelerated the conversion of TCE to ethene by 7–14 days. Members of the enrichments belong to the phyla Bacteroidetes, Chloroflexi, Proteobacteria and Firmicutes. According to the operational taxonomic units, main differences between the composition of the enrichment incubated at 8 °C and 18 °C occurred with relative abundance of acetogenic and fermentative species. In addition to the temperature, the site-specific origin of the microbial communities and the solid phase applied during the fermentation technique contributed to the development of a unique microbial composition., World Journal of Microbiology and Biotechnology, 36 (2), ISSN:0959-3993, ISSN:1573-0972

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).

An alkaliphilic and moderately halophilic strain characterized by optimal growth at pH 9.0–10.0 and 7 % (w/v) NaCl, and designated B16-24T, was isolated from the rhizosphere soil of the bayonet grass Bolboschoenus maritimus at a soda pond in the Kiskunsag National Park, Hungary. Cells of the strain were Gram-staining-positive, non-motile, straight rods, and formed central, ellipsoidal endospores with slightly swollen sporangia. The isolate was facultative anaerobic, catalase positive, oxidase negative, and contained a peptidoglycan of type A1γ based on meso-diaminopimelic acid. Menaquinone-7 (MK-7) was the predominant isoprenoid quinone, and anteiso-C15 : 0 the major cellular fatty acid. The DNA G+C content of strain B16-24T was 36.6 mol%. The 16S rRNA gene-based phylogenetic analysis revealed that the novel isolate had the greatest similarities to the type strains of Bacillus okhensis Kh10-101T (97.8 %), B. akibai 1139T (97.4 %), B. alkalisediminis K1-25T (97.3 %) and B. wakoensis N-1T (97.1 %). The DNA–DNA relatedness of strain B16-24T and the closely related Bacillus species ranged between 24±6 % and 35±3 %. The distinctive phenotypic and genetic results of this study confirmed that strain B16-24T represents a novel species within the genus Bacillus , for which the name Bacillus kiskunsagensis sp. nov. is proposed. The type strain is B16-24T (=DSM 29791T=NCAIM B.02610T).

A novel alphaproteobacterium was isolated from the well water of a thermal bath at Budapest, Hungary. Phylogenetic analysis of the novel strain showed that this bacterium belongs to a distinct lineage among the genus Brevundimonas . Based on the 16S rRNA gene sequence strain FDRGB2bT showed the highest sequence similarity values to Brevundimonas naejangsanensis BIO-TAS2-2T (97.35 %), Brevundimonas viscosa F3T (97.28 %), Brevundimonas vesicularis LMG 2350T (97.27 %), Brevundimonas nasdae GTC 1043T (97.14 %), Brevundimonas vancanneytii LMG 2337T (97.13 %) and Brevundimonas aurantiaca DSM 4731T (97.13 %). The newly isolated bacterium was strictly aerobic, and its optimum growth occurred at 20–30 °C, between pH 8–9 and without NaCl. Movement was with a single polar flagellum, but the cells could also produce stalks. The major isoprenoid quinone of strain FDRGB2bT was Q-10, the major cellular fatty acids were C18 : 1ω7c and C16 : 0, and the polar lipid profile contained phosphatidylglycerol, diphosphatidylglycerol, two unknown phospholipids and four unknown glycolipids. The characteristic diamino acid in its cell wall is meso-diaminopimelic acid. The G+C content of DNA of the type strain was 69.8 mol%. Strain FDRGB2bT (=DSM 29841T=NCAIM B.02621T) is proposed as the type strain of a novel species with the proposed name Brevundimonas balnearis sp. nov.

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).

Following the exposure of a biofilm sample from a hydrothermal spring cave (Gellert Hill, Budapest, Hungary) to gamma radiation, a strain designated FeSTC15-38T was isolated and studied by polyphasic taxonomic methods. The spherical-shaped cells stained Gram-negative, and were aerobic and non-motile. The pH range for growth was pH 6.0–9.0, with an optimum at pH 7.0. The temperature range for growth was 20–37 °C, with an optimum at 28 °C. Phylogenetic analysis based on the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus. The highest sequence similarities appeared with Deinococcus hopiensis KR-140T (94.1 %), Deinococcus aquaticus PB314T (93.3 %) and Deinococcus aerophilus 5516T-11T (92.7 %). The DNA G+C content of the novel strain was 68.2 mol%. The predominant fatty acids (>10 %) were iso-C16 : 0 and C16 : 1ω7c, and the cell-wall peptidoglycan type was A3β l-Orn–Gly2-3, corroborating the assignment of the strain to the genus Deinococcus. Strain FeSTC15-38T contained MK-8 as the major menaquinone and several unidentified phospholipids, glycolipids and phosphoglycolipids. Resistance to gamma radiation (D10) of strain FeSTC15-38T was

A novel bacterium, CAI-18bT, was isolated from a bioreactor that treated landfill leachate using an oligotrophic growth medium. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain CAI-18bT is a member of the genus Rufibacter, showing 97.1 % pairwise similarity to Rufibacter roseus H359T, 96.4 % to Rufibacter tibetensis 1351T, 96.4 % to Rufibacter glacialis MDT1-10-3T and 96.0 % to Rufibacter immobilis MCC P1T. Strain CAI-18bT was rod-shaped, motile, oxidase- and catalase-positive. The predominant fatty acids were iso-C15 : 0 (24.1 %) and iso-C17 : 1 I (22.3 %), the major respiratory quinone was MK-7, and the predominant polar lipids were phosphatidylethanolamine and an unknown aminophospholipid. The G+C content of the genomic DNA of strain CAI-18bT was 50.7 mol%. The novel bacterium can be distinguished from related type strains based on its ability to assimilate N-acetylglucosamine and gentiobiose. On the basis of the phenotypic, chemotaxonomic and molecular data, strain CAI-18bT represents a novel species of the genus Rufibacter, for which the name Rufibacter quisquiliarum sp. nov. is proposed. The type strain is CAI-18bT (=DSM 29854T=NCAIM B.02614T).

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.

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 Pinisolibacter ravus E9T (96.4 %) and Ancalomicrobium adetum 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).

Many industries use ultrapure water (UPW) for their operation. In spite of purification efforts, microbial contaminations are the major cause of manufacturing problems in these systems. In our experiments, the water purification system of a power plant was investigated: the microbiologically critical points of the ultrapure water purification system were located by checking the number and diversity of bacteria to determine the optimum operational unit for chemical intervention: the most contaminated site was the mixed-bed ion-exchange resin containing unit. Biocides were tested against bacteria previously isolated from the same system; effect of biocides was checked also in laboratory model systems, and based on the results, a biocide treatment was carried out in the mixed-bed ion-exchange resin columns of the working power plant. Kathon WT was the most effective from the studied chemicals, being effective already in low concentration against most studied microorganisms. In case of the handling of the mixed-bed ion-exchange resin, 8-h treatment with 25ppm biocide concentration was effective. Following the treatment, the quality of the produced UPW met the standards (specific electric conductivity was

Biochar is used to improve soil fertility and mitigate climate change by carbon sequestration. The potential of using biochar together with plant growth promoting rhizobacteria (PGPR) as a soil fertilization technique, offers an alternative way for sustainable agriculture. In the present study biochar and acid stress adapted PGPR inoculants were applied in three different quantities in order to improve soil fertility to enhance maize growth and crop yield in an acidic sandy soil (pH 4.4). The objective of the study was to monitor the effect of biochar on soil biota and on the inoculated PGP bacteria. Soil bacterial community structure was characterized with the genotyping sequence-aided terminal restriction fragment length polymorphism (T-RFLP) technique and the phenotyping phospholipid fatty acid analysis (PLFA). T-RFLP method was applied also for detecting and estimating the relative abundance of the inoculated PGP bacteria. Inocula immobilized on the biochar surface, as well as high doses of biochar treatments positively influenced the applied Azospirillum brasilense and Arthrobacter crystallopoietes abundances. In case of Azospirillum brasilense, the positive effect proved to be statistically significant (1–6 times higher relative abundances as compared to the control and small dose). The bacterial community structure in the rhizosphere was significantly influenced both by maize growth stage and by high doses (15 and 30 Mg ha−1) of biochar treatment. In the case of the immobilized PGP bacteria on the biochar surface treatment the maize above-ground biomass was significantly enhanced (2.6–3.2 times of the control). This study revealed that high doses of biochar treatment influenced the abundance of those bacterial groups that might play important roles in soil nutrient cycles.

Winter conditions in aquatic habitats of the temperate zone markedly differ from those present in warmer seasons, nevertheless, relatively scarce information is available on planktonic microbial composition, as sites are not easily accessible and it was supposed traditionally that microbial activity is low during this cold period. Since microorganisms could have great impact on the ecosystem even during winter, we explored various sites in the Eastern Carpathians regarding the abundance and taxonomic composition of planktonic microorganisms. Although many of the studied environments were extreme habitats, planktonic microbial communities were abundant and mostly diverse with the presence of previously unidentified taxa.

Observations of earthworm colonization on sites where they were absent previously, such as on post-mining heaps, indicate that they may substantially alter soil conditions as well as soil microbial communities. However, long-term effects of earthworms on microbial activity of soil ecosystems remains poorly understood. To improve this situation, we set up microcosm experiments with clay only, with clay and litter, and with clay, litter and earthworms. Microcosms were sampled after 3, 60, 180 and 395 days of cultivation and divided into three subsamples: clay, litter, and drilosphere (earthworm tunnels and associates casts), when present. Microbial respiration, microbial biomass carbon, species composition, metabolic activity using BIOLOG, PLFA concentration, isoprenoid quinones content and DGGE fingerprints were analysed in all microcosms and at all subsamples. Microbial biomass carbon and basal soil respiration were significantly affected by type of microcosms and time of sampling. Microbial biomass in drilosphere was significantly higher than in clay and litter. The CFU (colony forming units) were significantly affected by presence of earthworms having significantly higher CFU in drilosphere than in all other subsamples. Analysis of PLFA indicated highest relative biomass of fungi and bacteria in clay from microcosms with earthworms. The DGGE analysis showed various compositions of microbial communities among subsamples from various treatments taken at different time. Finally, our results revealed significant effect of earthworms on activity and biomass of soil microbial community under long-term laboratory incubation.

Nowadays, one of the most important challenges is to ensure sustainable agricultural management of crops such as maize (Zea mays L.). Long-term crop production, however, may influence the soil properties, the composition and activity of microbial communities. The aim of this study was to compare the catabolic activity and taxonomic diversity of bacterial communities inhabiting the soil of a non-fertilized maize monoculture and a natural grassland. Samples were taken from the horizons A and C in the first part of the vegetation period. MicroResp&trade, technique was used to explore the catabolic potential of microbial communities and next generation amplicon sequencing to reveal the bacterial diversity. Based on the catabolic activity results, higher differences were revealed among the soil horizons than the different land uses. The highest degree carbon source utilization was detected in the soil horizon A of the natural grassland. The taxonomic composition of bacterial communities was dominated by Proteobacteria. The relative abundance of other dominant phyla (Acidobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, Planctomycetes, Gemmatimonadetes, Chloroflexi and Patescibacteria) varied according to both the land use and soil depth. Amplicon sequences belonging to genera of r-strategist &ldquo, copiotrophic&rdquo, and K-strategist &ldquo, oligotrophic&rdquo, bacteria were identified from the soils of both maize monoculture and grassland.

Karst areas have great environmental importance as sources of subsurface water and often maintain very sensitive ecosystems. In recent years, increasing number of microbiological studies focused on the bacterial communities of karst soils. In this study, diversity examinations on two distinct Hungarian karst areas, Aggtelek and Tapolca, were performed using parallel cultivation and molecular cloning methods. The phylogenetic affiliation of bacterial strains and molecular clones was determined based on their 16S rRNA gene sequences. Bacterial isolates were identified as members of the phyla Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. Besides the taxa identified by cultivation, members of the phyla Chloroflexi, Cyanobacteria, Acidobacteria, Verrucomicrobia, and Gemmatimonadetes were detected by the cloning. The difference in the composition of soil bacterial communities was related to geographic locations and soil types. Both the highest and the lowest bacterial diversities were detected in samples from Aggtelek National Park, characterized by Leptic Luvisol and Rendzic Leptosol soil types. The difference in the composition of bacterial communities between Rendzic Leptosol and Leptic Phaeozem soil types at Tapolca could be the result of human impacts.

This study provides a comprehensive microbiological survey of three drinking water networks applying different water treatment processes. Variability of microbial communities was assessed by cultivation-based [nitrifying, denitrifying most probable number (MPN) heterotrophic plate count] and sequence-aided terminal restriction fragment length polymorphism (T-RFLP) analysis. The effect of microbial community composition on nitrifying MPN values was revealed. The non-treated well water samples showed remarkable differences to their corresponding distribution systems regarding low plate count, nitrifying MPN, and the composition of microbial communities, which increased and changed, respectively, in distribution systems. Environmental factors, such as pH, total inorganic nitrogen content (ammonium and nitrite concentration), and chlorine dioxide treatment had effect on microbial community compositions. The revealed heterogeneous nitrifying population achieved remarkable nitrification, which occurred at low ammonium concentration (14–51 μM) and slightly alkaline pH 7.7–7.9 in chlorine dioxide disinfected water networks. No change was observed in nitrification-generated nitrate concentration, although nitrate-reducing (and denitrifying) bacteria were present with low MPN and characterized by sequence-aided T-RFLP. The community structures of water samples partially changed in nitrifying enrichments and had influence on the generated nitrifying, especially nitrite-oxidizing MPN regarding the facilitated growth of nitrate-reducing bacteria and even methanogenic archaea beside ammonia-oxidizing microorganisms and nitrite-oxidizing bacteria.

A strain designated PYM3-14Twas isolated from the drinking water network of Budapest (Hungary) and was studied by polyphasic taxonomic methods. The straight-rod-shaped cells stained Gram-negative, were aerobic and non-motile. Phylogenetic analysis of the 16S rRNA gene sequence of strain PYM3-14Trevealed a clear affiliation with members of the familyXanthomonadaceaewithin the classGammaproteobacteria. The 16S rRNA gene sequence of strain PYM3-14Tshowed the closest sequence similarities toArenimonas daechungensisCH15-1T(96.2 %),Arenimonas oryziterraeYC6267T(95.2 %) andLysobacter brunescensUASM DT(94.4 %). The DNA G+C content of strain PYM3-14T, measured by two different methods (52.0 mol% and 55.9 mol%, respectively), was much lower than that of any member of the genusArenimonas. The predominant fatty acids (>8 %) were iso-C16:0, iso-C15:0, iso-C14:0, iso-C17:1ω9cand C16:1ω7calcohol. Strain PYM3-14Tcontained Q-8 as the major ubiquinone and phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylmonomethylethanolamine as the major polar lipids. According to phenotypic and genotypic data strain PYM3-14Trepresents a novel species of the genusArenimonas, for which the nameArenimonas subflavasp. nov. is proposed. The type strain is PYM3-14T( = NCAIM B 02508T = DSM 25526T). On the basis of new data obtained in this study, an emended description of the genusArenimonasis also proposed.

Effect of carrier texture and type on biofilm development and maturation were studied on an eight-reactors-containing pilot-scale cascade system which treated municipal wastewater under aerobic conditions and various system operational characteristics. Dissimilarities in the biofilm structures grown on four types of polymer fiber-based carriers placed in the reactors having different role during wastewater purification and compositional changes of bacterial communities during biofilm maturation were clearly observable. In the first 2–3 weeks, taxonomic diversity of biofilm bacterial communities increased and reached their maximum values. Carrier type and texture had comparable effect on the weight, activity and composition of biofilms as the wastewater matrix. Biofilm community grown on the carrier having the best colonization properties were dominated by Proteobacteria, Synergistetes, Bacteroidetes and Firmicutes. In the nascent 7-days-old biofilm, aerobic chemoorganotrophic genera, while in the mature 45-days-old biofilm anaerobes, such as sulfate-reducer and fermentative genera were the major members of the bacterial communities.

Naturally occurring and anthropogenic petroleum hydrocarbons are potential carbon sources for many bacteria. The AlkB-related alkane hydroxylases, which are integral membrane non-heme iron enzymes, play a key role in the microbial degradation of many of these hydrocarbons. Several members of the genus Rhodococcus are well-known alkane degraders and are known to harbor multiple alkB genes encoding for different alkane 1-monooxygenases. In the present study, 48 Rhodococcus strains, representing 35 species of the genus, were investigated to find out whether there was a dominant type of alkB gene widespread among species of the genus that could be used as a phylogenetic marker. Phylogenetic analysis of rhodococcal alkB gene sequences indicated that a certain type of alkB gene was present in almost every member of the genus Rhodococcus. These alkB genes were common in a unique nucleotide sequence stretch absent from other types of rhodococcal alkB genes that encoded a conserved amino acid motif: WLG(I/V/L)D(G/D)GL. The sequence identity of the targeted alkB gene in Rhodococcus ranged from 78.5 to 99.2% and showed higher nucleotide sequence variation at the inter-species level compared to the 16S rRNA gene (93.9-99.8%). The results indicated that the alkB gene type investigated might be applicable for: (i) differentiating closely related Rhodococcus species, (ii) properly assigning environmental isolates to existing Rhodococcus species, and finally (iii) assessing whether a new Rhodococcus isolate represents a novel species of the genus.

An alkaliphilic and moderately halophilic bacterial strain characterized by optimal growth at pH 9.0–10.0 and with 5–7 % (w/v) NaCl, designated BV-35T, was isolated from water of a soda pan located in Kiskunsag National Park, Hungary. Cells of the orange-pigmented colony were Gram-stain-positive, non-motile and non-endospore-forming coccoid rods. The isolate was strictly aerobic, catalase-positive and oxidase-negative. Strain BV-35T displayed a peptidoglycan similar to type A4α, l-Lys–l-Glu (A11.54 according to www.peptidoglycan-types.info) but containing additionally 4-aminobutyric acid. Menaquinone-7 (MK-7) was the predominant isoprenoid quinone, and anteiso-C15 : 0 and anteiso-C17 : 0 were its major cellular fatty acids. The DNA G+C content of strain BV-35T was 65.4 mol%. Based on 16S rRNA gene sequence similarities, the novel isolate showed the closest relationship to Nesterenkonia populi GP 10-3T (97.9 %). The DNA–DNA relatedness between BV-35T and N. populi was 46.7 %. The distinguishing phenotypic and genetic results of this polyphasic study revealed that strain BV-35T represents a novel member of the genus Nesterenkonia , for which the name Nesterenkonia pannonica sp. nov. is proposed. The type strain is BV-35T (=DSM 29786T=NCAIM B 02606T).

The Buda Thermal Karst System is an active hypogenic karst area that offers possibility for the analysis of biogenic cave formation. The aim of the present study was to gain information about morphological structure and genetic diversity of bacterial communities inhabiting the Diana-Hygieia Thermal Spring (DHTS). Using scanning electron microscopy, metal accumulating and unusual reticulated filaments were detected in large numbers in the DHTS biofilm samples. The phyla Actinobacteria, Firmicutes and Proteobacteria were represented by both bacterial strains and molecular clones but phyla Acidobacteria, Chlorobi, Chlorofexi, Gemmatimonadetes, Nitrospirae and Thermotogae only by molecular clones which showed the highest similarity to uncultured clone sequences originating from different environmental sources. The biofilm bacterial community proved to be somewhat more diverse than that of the water sample and the distribution of the dominant bacterial clones was different between biofilm and water samples. The majority of biofilm clones was affiliated with Deltaproteobacteria and Nitrospirae while the largest group of water clones was related to Betaproteobacteria. Considering the metabolic properties of known species related to the strains and molecular clones from DHTS, it can be assumed that these bacterial communities may participate in the local sulphur and iron cycles, and contribute to biogenic cave formation.

Geothermal wells characterized by thermal waters warmer than 30°C can be found in more than 65% of the area of Hungary. The examined thermal wells located nearby Szarvas are used for heating industrial and agricultural facilities because of their relatively high hydrocarbon content. The aim of this study was to reveal the prokaryotic community structure of the water of SZR18, K87 and SZR21 geothermal wells using molecular cloning methods and Denaturing Gradient Gel Electrophoresis (DGGE). Water samples from the outflow pipes were collected in 2012 and 2013. The phylogenetic distribution of archaeal molecular clones was very similar in each sample, the most abundant groups belonged to the genera Methanosaeta, Methanothermobacter and Thermofilum. In contrast, the distribution of bacterial molecular clones was very diverse. Many of them showed the closest sequence similarities to uncultured clone sequences from similar thermal environments. From the water of the SZR18 well, phylotypes closely related to genera Fictibacillus and Alicyclobacillus (Firmicutes) were only revealed, while the bacterial diversity of the K87 well water was much higher. Here, the members of the phyla Thermodesulfobacteria, Proteobacteria, Nitrospira, Chlorobi, OP1 and OPB7 were also detected besides Firmicutes.

A novel bacterium, PB3-7BT, was isolated on phenol-supplemented inorganic growth medium from a laboratory-scale wastewater purification system that treated coke plant effluent. 16S rRNA gene sequence analysis revealed that strain PB3-7BT belonged to the family Alcaligenaceae and showed the highest pairwise sequence similarity to Parapusillimonas granuli Ch07T (97.5 %), Candidimonas bauzanensis BZ59T (97.3 %) and Pusillimonas noertemannii BN9T (97.2 %). Strain PB3-7BT was rod-shaped, motile and oxidase- and catalase-positive. The predominant fatty acids were C16 : 0, C17 : 0 cyclo, C19 : 0 cyclo ω8c and C14 : 0 3-OH, and the major respiratory quinone was Q-8. The G+C content of the genomic DNA of strain PB3-7BT was 59.7 mol%. The novel bacterium can be distinguished from closely related type strains based on its urease activity and the capacity for assimilation of glycerol and amygdalin. On the basis of the phenotypic, chemotaxonomic and molecular data, strain PB3-7BT is considered to represent a new genus and species, for which the name Eoetvoesia caeni gen. nov., sp. nov. is proposed. The type strain of Eoetvoesia caeni is PB3-7BT ( = DSM 25520T = NCAIM B 02512T).

Bacterial communities of a bank-filtered drinking water system were investigated by aerobic cultivation and clone library analysis. Moreover, bacterial communities were compared using sequence-aided terminal restriction fragment length polymorphism (T-RFLP) fingerprinting at ten characteristic points located at both the collecting and the distributing part of the water supply system. Chemical characteristics of the samples were similar, except for the presence of chlorine residuals in the distribution system and increased total iron concentration in two of the samples. Assimilable organic carbon (AOC) concentration increased within the collection system, it was reduced by chlorination and it increased again in the distribution system. Neither fecal indicators nor pathogens were detected by standard cultivation techniques. Chlorination reduced bacterial diversity and heterotrophic plate counts. Community structures were found to be significantly different before and after chlorination: the diverse communities in wells and the collection system were dominated by chemolithotrophic (e.g., Gallionella and Nitrospira) and oligocarbophilic-heterotrophic bacteria (e.g., Sphingomonas, Sphingopyxis, and Bradyrhizobium). After chlorination in the distribution system, the most characteristic bacterium was related to the facultative methylotrophic Methylocella spp. Communities changed within the distribution system too, Mycobacterium spp. or Sphingopyxis spp. became predominant in certain samples.

Strains of a novel alphaproteobacterium were isolated from ultrapure water of a Hungarian power plant on a newly developed medium. Phylogenetic analysis of the 16S rRNA gene sequences of the novel strains showed that these bacteria belong to a distinct lineage far from any known taxa. Based on the 16S rRNA gene sequences, strains PI_31, PI_25 and PI_21T exhibited the highest sequence similarity to Bosea minatitlanensis AMX51T (93.43 %) and Bosea thiooxidans DSM 9653T (93.36 %); similarity to all other taxa was less than 93.23 %. Fatty acid profiles, matrix-assisted laser-desorption/ionization time-of-flight mass spectra of cell extracts as well as physiological and biochemical characteristics indicated that our strains represent a novel genus and species within the class Alphaproteobacteria . The major isoprenoid quinone of the strains was Q-10, the major cellular fatty acids were C18 : 1ω7c and 11-methyl C18 : 1ω7c and the polar lipid profiles of the strains contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and several unknown phospholipids and other lipids. The characteristic diamino acid in their cell wall was meso-diaminopimelic acid. The G+C content of DNA of the proposed type strain PI_21T was 68.9 mol%. A new genus and species, Phreatobacter oligotrophus gen. nov., sp. nov., is proposed to accommodate the strains. Strain PI_21T ( = DSM 25521T = NCAIM B 02510T) is the type strain of Phreatobacter oligotrophus.

A Gram-staining-negative, rod-shaped and motile bacterium, designated strain ERB1-3T, was isolated from a laboratory-scale activated sludge system treating coke plant effluent using thiocyanate-supplemented growth medium. Strain ERB1-3T was oxidase-positive and weakly catalase-positive. The predominant fatty acids were C18 : 1ω7c (35.6 %) and C17 : 1ω6c (29.2 %), and the major respiratory quinone was Q-10. Polar lipids were dominated by sphingoglycolipid and phosphatidylglycerol. Major polyamines were spermidine and sym-homospermidine. The G+C content of the genomic DNA of strain ERB1-3T was 66.4 mol%. Based on the 16S rRNA gene, strain ERB1-3T exhibited the highest sequence similarity values to Sphingomonas sanxanigenens DSM 19645T (96.1 %), Sphingobium scionense DSM 19371T (95.1 %) and Stakelama pacifica LMG 24686T (94.8 %) within the family Sphingomonadaceae . The novel isolate had some unique chemotaxonomic features that differentiated it from these closely related strains, contained much more C17 : 1ω6c, C15 : 0 2-OH, C17 : 0 and C17 : 1ω8c fatty acids and possessed diphosphatidylglycerol only in trace amounts. On the basis of the phenotypic, chemotaxonomic and molecular data, strain ERB1-3T is considered to represent a novel genus and species, for which the name Hephaestia caeni gen. nov., sp. nov. is proposed. The type strain is ERB1-3T ( = DSM 25527T = NCAIM B 02511T).

The effect of vertical physico-chemical stratification on the planktonic microbial community composition of the deep, hypersaline and heliothermal Lake Ursu (Sovata, Romania) was examined in this study. On site and laboratory measurements were performed to determine the physical and chemical variables of the lake water, and culture-based and cultivation-independent techniques were applied to identify the members of microbial communities. The surface of the lake was characterized by a low salinity water layer while the deepest region was extremely saline (up to 300 g/L salinity). Many parameters (e.g. photosynthetically active radiation, dissolved oxygen concentration, pH, redox potential) changed dramatically from 2 to 4 m below the water surface in conjunction with the increasing salinity values. The water temperature reached a maximum at this depth. At around 3 m depth, there was a water layer with high (bacterio) chlorophyll content dominated by Prosthecochloris vibrioformis, a phototrophic green sulfur bacterium. Characteristic microbial communities with various prokaryotic taxa were identified along the different environmental parameters present in the different water layers. Some of these bacteria were known to be heterotrophic and therefore may be involved in the decomposition of lake organic material (e.g. Halomonas, Idiomarina and Pseudoalteromonas) while others in the transformation of sulfur compounds (e.g. Prosthecochloris). Eukaryotic microorganisms identified by molecular methods in the lake water belonged to genera of green algae (Mantionella and Picochlorum), and were restricted mainly to the upper layers.

The results of 16S rRNA, gyrB and catA gene sequence comparisons and reasserted DNA–DNA hybridization unambiguously proved that Rhodococcus jialingiae Wang et al. 2010 and Rhodococcus qingshengii Xu et al. 2007 represent a single species. On the basis of priority R. jialingiae must be considered a later synonym of R. qingshengii .

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.