Sphingobium aquiterrae sp. nov., a toluene, meta- and para-xylene-degrading bacterium isolated from petroleum hydrocarbon-contaminated groundwater.

A Gram-negative, aerobic, slightly yellow-pigmented bacterium, designated as SKLS-A10T, was isolated from groundwater sample of the 'Siklós' petroleum hydrocarbon contaminated site (Hungary). Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain SKLS-A10T formed a distinct phyletic lineage within the genus Sphingobium. It shared the highest 16S rRNA gene homology with Sphingobium abikonense DSM 23268T (97.29 %), followed by Sphingobium lactosutens DSM 23389T (97.23 %), Sphingobium phenoxybenzoativorans KCTC 42448T (97.16 %) and Sphingobium subterraneum NBRC 109814T (96.74 %). The predominant fatty acids (>5 % of the total) are C18 : 1ω7c, C14 : 0 2-OH, C16 : 1ω7c/iso C15 : 0 2-OH, C17 : 1ω6c and C16 : 0. The major ubiquinone is Q-10. The predominant polyamine is spermidine. The major polar lipids are sphingoglycolipid and diphosphatidylglycerol. The DNA G+C content of strain SKLS-A10T is 65.9 mol%. On the basis of evidence from this taxonomic study using a polyphasic approach, strain SKLS-A10T represents a novel species of the genus Sphingobium for which the name Sphingobiumaquiterrae sp. nov. is proposed. The type strain is SKLS-A10T (=DSM 106441T=NCAIM B. 02634T).

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).

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).

Deinococcus budaensis sp. nov., a mesophilic species isolated from a biofilm sample of a hydrothermal spring cave.

Following the exposure of a biofilm sample from a hydrothermal spring cave (Gellért 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 A3ß 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 <3.0 kGy. According to phenotypic and genotypic data, strain FeSTC15-38T represents a novel species for which the name Deinococcus budaensis sp. nov. is proposed. The type strain is FeSTC15-38T (=NCAIM B.02630T=DSM 101791T).

Rufibacter quisquiliarum sp. nov., a new member of the phylum Bacteroidetes isolated from a bioreactor treating landfill leachate.

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).

Arenimonas subflava sp. nov., isolated from a drinking water network, and emended description of the genus Arenimonas.

A strain designated PYM3-14T was 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 PYM3-14T revealed a clear affiliation with members of the family Xanthomonadaceae within the class Gammaproteobacteria. The 16S rRNA gene sequence of strain PYM3-14T showed the closest sequence similarities to Arenimonas daechungensis CH15-1T (96.2 %), Arenimonas oryziterrae YC6267T (95.2 %) and Lysobacter brunescens UASM 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 genus Arenimonas. The predominant fatty acids (>8 %) were iso-C16:0, iso-C15:0, iso-C14:0, iso-C17:1ω9c and C16:1ω7c alcohol. Strain PYM3-14T contained Q-8 as the major ubiquinone and phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylmonomethylethanolamine as the major polar lipids. According to phenotypic and genotypic data strain PYM3-14T represents a novel species of the genus Arenimonas, for which the name Arenimonas subflava sp. 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 genus Arenimonas is also proposed.

Characterization of wheat straw-degrading anaerobic alkali-tolerant mixed cultures from soda lake sediments by molecular and cultivation techniques.

Alkaline pretreatment has the potential to enhance the anaerobic digestion of lignocellulosic biomass to biogas. However, the elevated pH of the substrate may require alkalitolerant microbial communities for an effective digestion. Three mixed anaerobic lignocellulolytic cultures were enriched from sediments from two soda lakes with wheat straw as substrate under alkaline (pH 9) mesophilic (37°C) and thermophilic (55°C) conditions. The gas production of the three cultures ceased after 4 to 5 weeks, and the produced gas was composed of carbon dioxide and methane. The main liquid intermediates were acetate and propionate. The physiological behavior of the cultures was stable even after several transfers. The enrichment process was also followed by molecular fingerprinting (terminal restriction fragment length polymorphism) of the bacterial 16S rRNA gene and of the mcrA/mrtA functional gene for methanogens. The main shift in the microbial community composition occurred between the sediment samples and the first enrichment, whereas the structure was stable in the following transfers. The bacterial communities mainly consisted of Sphingobacteriales, Clostridiales and Spirochaeta, but differed at genus level. Methanothermobacter and Methanosarcina genera and the order Methanomicrobiales were predominant methanogenes in the obtained cultures. Additionally, single cellulolytic microorganisms were isolated from enrichment cultures and identified as members of the alkaliphilic or alkalitolerant genera. The results show that anaerobic alkaline habitats harbor diverse microbial communities, which can degrade lignocellulose effectively and are therefore a potential resource for improving anaerobic digestion.

Zoogloea oleivorans sp. nov., a floc-forming, petroleum hydrocarbon-degrading bacterium isolated from biofilm.

A floc-forming, Gram-stain-negative, petroleum hydrocarbon-degrading bacterial strain, designated Buc(T), was isolated from a petroleum hydrocarbon-contaminated site in Hungary. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Buc(T) formed a distinct phyletic lineage within the genus Zoogloea. Its closest relative was found to be Zoogloea caeni EMB43(T) (97.2% 16S rRNA gene sequence similarity) followed by Zoogloea oryzae A-7(T) (95.9%), Zoogloea ramigera ATCC 19544(T) (95.5%) and Zoogloea resiniphila DhA-35(T) (95.4%). The level of DNA-DNA relatedness between strain Buc(T) and Z. caeni EMB43(T) was 31.6%. Cells of strain Buc(T) are facultatively aerobic, rod-shaped, and motile by means of a polar flagellum. The strain grew at temperatures of 5-35 °C (optimum 25-28 °C), and at pH 6.0-9.0 (optimum 6.5-7.5). The predominant fatty acids were C16:0, C10 : 0 3-OH, C12:0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The major respiratory quinone was ubiquinone-8 (Q-8) and the predominant polar lipid was phosphatidylethanolamine. The genomic DNA G+C content was 63.2 mol%. On the basis of the chemotaxonomic, molecular and phenotypic data, isolate Buc(T) is considered to represent a novel species of the genus Zoogloea, for which the name Zoogloea oleivorans sp. nov. is proposed. The type strain is Buc(T) ( =DSM 28387(T) =NCAIM B 02570(T)).

Eoetvoesia caeni gen. nov., sp. nov., isolated from an activated sludge system treating coke plant effluent.

A novel bacterium, PB3-7B(T), 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 PB3-7B(T) belonged to the family Alcaligenaceae and showed the highest pairwise sequence similarity to Parapusillimonas granuli Ch07(T) (97.5%), Candidimonas bauzanensis BZ59(T) (97.3%) and Pusillimonas noertemannii BN9(T) (97.2%). Strain PB3-7B(T) was rod-shaped, motile and oxidase- and catalase-positive. The predominant fatty acids were C(16 : 0), C(17 : 0) cyclo, C(19 : 0) cyclo ω8c and C(14 : 0) 3-OH, and the major respiratory quinone was Q-8. The G+C content of the genomic DNA of strain PB3-7B(T) 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 PB3-7B(T) 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 PB3-7B(T) ( = DSM 25520(T) = NCAIM B 02512(T)).

Vertical physico-chemical gradients with distinct microbial communities in the hypersaline and heliothermal Lake Ursu (Sovata, Romania).

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.

Hephaestia caeni gen. nov., sp. nov., a novel member of the family Sphingomonadaceae isolated from activated sludge.

A Gram-staining-negative, rod-shaped and motile bacterium, designated strain ERB1-3(T), was isolated from a laboratory-scale activated sludge system treating coke plant effluent using thiocyanate-supplemented growth medium. Strain ERB1-3(T) 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 ERB1-3(T) was 66.4 mol%. Based on the 16S rRNA gene, strain ERB1-3(T) exhibited the highest sequence similarity values to Sphingomonas sanxanigenens DSM 19645(T) (96.1%), Sphingobium scionense DSM 19371(T) (95.1%) and Stakelama pacifica LMG 24686(T) (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 ERB1-3(T) 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 ERB1-3(T) ( = DSM 25527(T) = NCAIM B 02511(T)).

The effect of easily degradable substrate feeding on the community structure of laboratory-scale wastewater sludge digesters.

The effect of several easily degradable substrates, such as protein, starch and sunflower oil was investigated on the bacterial community of a laboratory-scale biogas model system. Besides measuring gas yield, Denaturing Gradient Gel Electrophoresis (DGGE), Phospholipids Fatty Acid Analysis (PLFA) for Bacteria and T-RFLP analysis of the mcrA gene for Archaea were used. The community of the examined biogas reactors adapted to the new substrates through a robust physiological reaction followed by moderate community abundance shifts. Gas yield data clearly demonstrated the physiological adaptation to substrate shifts. Statistical analysis of DNA and chemotaxonomic biomarkers revealed community abundance changes. Sequences gained from DGGE bands showed the dominance of the phyla Bacteroidetes and the presence of Firmicutes (Clostridia) and Thermotogae. This was supported by the detection of large amounts of branched 15-carbon non-hydroxy fatty acids in PLFA profiles, as common PLFA markers of the Bacteroidetes group. Minor abundance ratios changes were observed in the case of Archaea in accordance with changes of the fed substrates.

Application of special oligotrophic media for cultivation of bacterial communities originated from ultrapure water.

Because of the selectivity of the commonly used media it is very difficult to cultivate bacteria inhabiting ultrapure waters under laboratory conditions. In this study 5 new media (synthetic and complex) were developed to reveal bacterial community of the ultrapure water originated from the water purification system of a Hungarian power plant which was studied already with using traditional media. Composition of the new media tends to reproduce the nutrient deficient conditions of the investigated water, therefore media were highly oligotrophic. Altogether 122 bacterial strains were isolated from the 5 different media. Based on ARDRA grouping 27 strains were chosen for the partial 16S rRNA gene sequence analysis. The results showed that the applied media strongly influence the composition of the cultivable bacterial community. A larger scale of α-Proteobacteria (Mesorhizobium spp., Ancylobacter sp., Methylobacterium sp.) and many Actinobacteria (Leifsonia sp., Microbacterium spp., Mycobacterium spp.) could be isolated from the same ultrapure water system than with any other cultivation methods or media applied before. Moreover, two novel bacterial taxa could be isolated from the studied water purification system.

Performance characteristics of qPCR assays targeting human- and ruminant-associated bacteroidetes for microbial source tracking across sixteen countries on six continents.

Numerous quantitative PCR assays for microbial fecal source tracking (MST) have been developed and evaluated in recent years. Widespread application has been hindered by a lack of knowledge regarding the geographical stability and hence applicability of such methods beyond the regional level. This study assessed the performance of five previously reported quantitative PCR assays targeting human-, cattle-, or ruminant-associated Bacteroidetes populations on 280 human and animal fecal samples from 16 countries across six continents. The tested cattle-associated markers were shown to be ruminant-associated. The quantitative distributions of marker concentrations in target and nontarget samples proved to be essential for the assessment of assay performance and were used to establish a new metric for quantitative source-specificity. In general, this study demonstrates that stable target populations required for marker-based MST occur around the globe. Ruminant-associated marker concentrations were strongly correlated with total intestinal Bacteroidetes populations and with each other, indicating that the detected ruminant-associated populations seem to be part of the intestinal core microbiome of ruminants worldwide. Consequently tested ruminant-targeted assays appear to be suitable quantitative MST tools beyond the regional level while the targeted human-associated populations seem to be less prevalent and stable, suggesting potential for improvements in human-targeted methods.

Phylogenetic diversity of bacterial and archaeal communities inhabiting the saline Lake Red located in Sovata, Romania.

Lake Red is one of the saline lakes which were formed as a consequence of salt massif dissolution at the foot of the Gurghiu Mountains (Central Romania) at the end of the nineteenth century. The lake water had approximately 15 % w/v salt content. Phylogenetic diversity of prokaryotes inhabiting the water and sediment of the lake was studied using cultivation and cultivation-independent methods following a sampling in spring 2009. According to the results of 16S rRNA gene-based denaturing gradient gel electrophoresis (DGGE), the richness of Bacteria was higher than Archaea on the basis of the number and position of dominant bands in the gel. Sequences from DGGE bands were affiliated with Gammaproteobacteria (Halomonas and Alkalilimnicola) and Bacteroidetes (Psychroflexus) as well as Euryarchaeota. Cultivation from five different saline media resulted in 101 bacterial strains of which Gammaproteobacteria (Halomonas, Marinobacter and Salinivibrio) were the most abundant. Firmicutes (Bacillus) and Alphaproteobacteria (Aurantimonas and Roseovarius) were also identified among the isolated strains. The 16S rRNA genes from 82 bacterial and 95 archaeal clones were also phylogenetically analyzed. Bacterial clones were related to various genera of Gammaproteobacteria (Alkalilimnicola, Alkalispirillum, Arhodomonas, Halomonas, Saccharospirillum), Bacteroidetes (Gracilimonas, Psychroflexus) and Alphaproteobacteria (Oceanicola, Roseinatronobacter, Roseovarius). All of the archaeal clones sequenced corresponded to a homologous cluster affiliated with Halopelagius.

Thermus composti sp. nov., isolated from oyster mushroom compost.

A Gram-stain-negative, rod-shaped bacterium (strain K-39(T)) was isolated from the thermophilic phase of the composting process for oyster mushroom substrate preparation. The strain grew at 40-80 °C (optimum, 65-75 °C), at pH 5-9 (optimum, pH 7), in media containing up to 1.5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain K-39(T) formed a distinct lineage within the genus Thermus. Its closest cultivated relative was Thermus islandicus PRI 3838(T) (96.8% similarity). The DNA G+C content of strain K-39(T) was 71.3 mol%. The new strain could be differentiated from the related taxa by not being able to hydrolyse starch. The predominant fatty acids of strain K-39(T) were iso-C(17:0) and anteiso-C(17:0). Strain K-39(T) contained a lower amount of the fatty acid iso-C(15:0) as compared to related species of the genus Thermus. The predominant respiratory quinone of the new isolate was menaquinone MK-8. On the basis of a taxonomic study using a polyphasic approach, strain K-39(T) is considered to represent a novel species of the genus Thermus, for which the name Thermus composti sp. nov. is proposed. The type strain is K-39(T) (=DSM 21686(T)=NCAIM B 02340(T)).

Bacterial communities in the gut of the freshwater copepod Eudiaptomus gracilis.

Eudiaptomus gracilis is the most abundant member of the zooplankton, plays a key role in the food web of Lake Balaton (Hungary). In the present study the composition of bacterial communities of this copepod was investigated based on cultivation and molecular cloning. The cultivated bacterial strains from the gut homogenate samples of Eudiaptomus gracilis belonged to four different clades: Firmicutes, Actinobacteria, Bacteriodetes and Proteobacteria. Clone library showed high species diversity, Firmicutes, Actinobacteria, Proteobacteria, representatives of Deinococcus-Thermus lineage and Cyanobacteria were detected. The isolated strains were very effective in degradation of different biopolymers. Many of the detected bacteria are known as opportunistic human or fish pathogens (Pseudomonas spp., Aeromonas spp., Chryseobacterium sp. and Staphylococcus sp.).

Bacterial communities in an ultrapure water containing storage tank of a power plant.

Ultrapure waters (UPWs) containing low levels of organic and inorganic compounds provide extreme environment. On contrary to that microbes occur in such waters and form biofilms on surfaces, thus may induce corrosion processes in many industrial applications. In our study, refined saltless water (UPW) produced for the boiler of a Hungarian power plant was examined before and after storage (sampling the inlet [TKE] and outlet [TKU] waters of a storage tank) with cultivation and culture independent methods. Our results showed increased CFU and direct cell counts after the storage. Cultivation results showed the dominance of aerobic, chemoorganotrophic α-Proteobacteria in both samples. In case of TKU sample, a more complex bacterial community structure could be detected. The applied molecular method (T-RFLP) indicated the presence of a complex microbial community structure with changes in the taxon composition: while in the inlet water sample (TKE) α-Proteobacteria (Sphingomonas sp., Novosphingobium hassiacum) dominated, in the outlet water sample (TKU) the bacterial community shifted towards the dominance of α-Proteobacteria (Rhodoferax sp., Polynucleobacter sp., Sterolibacter sp.), CFB (Bacteroidetes, formerly Cytophaga-Flavobacterium-Bacteroides group) and Firmicutes. This shift to the direction of fermentative communities suggests that storage could help the development of communities with an increased tendency toward corrosion.

A simple and novel volumetric method to metre low gas flows from laboratory-scale bioreactors and its application on laboratory sludge digesters.

A novel, cheap and easy to use method has been developed to measure low gas yields in bioreactors, based on the principle of bubble counting via digital imaging techniques and pattern recognition. No external hardware control is required for the measurements, and the device can be turned into a multichannel tool without further detector accessories. The method proved to perform outstandingly according to the testing and calibrating measurements against standard gas flow and revealed a short periodicity in the gas yields of two parallel laboratory-scale mesophilic biogas reactors providing well analysable data about them. For exact characterization of the oscillation, the data were converted into Morell wavelet spectra, which showed that every feeding period had a characteristic and similarly shaped wavelet profile, thereby this rhythm must have had an immanent source in the community metabolism, and it was not an artefact.

Tahibacter aquaticus gen. nov., sp. nov., a new gammaproteobacterium isolated from the drinking water supply system of Budapest (Hungary).

Three Gram-stain negative, aerobic, non-motile, non-spore-forming, rod-shaped bacterial strains, PYM5-11(T), RaM5-2 and PYM5-8, were isolated from the drinking water supply system of Budapest (Hungary) and their taxonomic positions were investigated by a polyphasic approach. All three strains grew optimally at 20-28°C and pH 5-7 without NaCl. The G+C content of the DNA of the type strain was 65.4mol%. On the basis of 16S rRNA gene sequence analysis, the isolates showed 94.5-94.9% sequence similarity to the type strain of Dokdonella koreensis and a similarity of 93.0-94.1% to the species of the genera Aquimonas and Arenimonas. The major isoprenoid quinone of the strains was ubiquinone Q-8. The predominant fatty acids were iso-C(15:0), iso-C(17:1)ω9c, C(16:1)ω7c, and C(16:0). Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine, as well as several unidentified aminolipids and phospholipids were present. The 16S rRNA gene sequence analysis, the predominant fatty acids, the polar lipid composition, RiboPrint patterns, physiological and biochemical characteristics showed that the three strains were related but distinct from the type strains of the four recognized species of the genus Dokdonella, and indicated that the strains represented a new genus within the Gammaproteobacteria. The strain PYM5-11 (=DSM 21667(T)=NCAIM B 02337(T)) is proposed as the type strain of a new genus and species, designated as Tahibacter aquaticus gen. nov., sp. nov.