Aquimonas voraii gen. nov., sp. nov., a novel gammaproteobacterium isolated from a warm spring of Assam, India

Substrate loading rates conducive to nitritation in entrapped cell reactors: performance and microbial community structure

This study aimed to elucidate the boundaries of ammonia and organic loading rates that allow for nitritation in continuous flow phosphorylated-polyvinyl alcohol entrapped cell reactors and to clarify the community structure of microorganisms involving nitrogen transformation in the gel bead matrices. At operating bulk dissolved oxygen concentration of 2 mg/L, nitritation was accomplished when the total ammonia nitrogen (TAN) loading rate was ≥ 0.3 kgN/m³/d. At TAN loading rates of ≤ 0.2 kgN/m³ /d, complete oxidation of ammonia to nitrate took place. Nitritation performance dropped with increased chemical oxygen demand (COD) loading rates indicating limitation of nitritation reactor operation at some COD loading conditions. 16S rRNA gene amplicon sequencing revealed that the uncultured Cytophagaceae bacterium, Arenimonas, Truepera, Nitrosomonas, Comamonas, unclassified Soil Crenarchaeotic Group, and uncultured Chitinophagaceae bacterium were highly abundant taxa in the reactors' gel bead matrices. qPCR with specific primers targeting amoA genes demonstrated the coexistence of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea, and Comammox in the gel bead matrices. AOB was likely the main functioning ammonia-oxidizing microorganisms due to the amoA gene being of highest abundance in most of the studied conditions. Nitrite-oxidizing microorganisms presented in less relative abundance than ammonia-oxidizing microorganisms, with Nitrobacter rather than Nitrospira dominating in the group. Results obtained from this study are expected to further the application of nitritation entrapped cell reactors to real wastewater treatment processes.

CO2 improves the microalgal-bacterial granular sludge towards carbon-negative wastewater treatment

As a promising wastewater treatment technology, little is known about whether the greenhouse gas CO₂ can be applied for microalgal-bacterial granular sludge (MBGS) process. This article applied CO₂ for improving MBGS process. It was found that the physical structure of MBGS with no CO₂ addition appeared to have a trend to be loose and disintegrated, with a sludge volume index at 5 min (SVI₅) of over 150 mL/g and an average pore size of 35 nm in 60 d operation. However, CO₂ could maintain the compact and integrated structure of MBGS with a SVI₅ lower than 50 mL/g and an average pore size ranging from 10 to 13 nm. CO₂ could enhance the production of extracellular polysaccharides and aromatic protein, thus favoring the granular stability of MBGS. CO₂ could change the aqueous environment, e.g. lowering the pH values, which resulted in different microbial communities as well as metabolic potentials of MBGS. As for the reactor performance, CO₂ could significantly improve the removals of organics and phosphorus, evidenced by the enhancement of genes encoding acetate-CoA ligase and ATPase, respectively. Although the mass ratio of algae to bacteria was elevated by CO₂ addition, the ammonia removal related enzymes of glutamate dehydrogenase and glutamine synthetase could be negatively and positively impacted by CO₂, respectively. Mass balance analysis of carbon indicated that CO₂ could provide additional carbon source as well as enhance the buffering capacity for the MBGS system. Further estimations suggested that the MBGS process could achieve a carbon-negative objective for municipal wastewater treatment by supplying CO₂ as additional carbon source. Hence, CO₂ supply for MBGS process in municipal wastewater treatment can be deemed as a two-birds-one-stone strategy, i.e. maintaining the granular stability and eliminating the carbon emission. This article can advance our basic knowledge on MBGS process towards environment-sustainable wastewater treatment.

Denitrifying bio-cathodes developed from constructed wetland sediments exhibit electroactive nitrate reducing biofilms dominated by the genera Azoarcus and Pontibacter

To limit the nitrate contamination of ground and surface water, stimulation of denitrification by electrochemical approach is an innovative way to be explored. Two nitrate reducing bio-cathodes were developed under constant polarization (-0.5 V vs SCE) using sediments and water from a constructed wetland (Rampillon, Seine-et-Marne, France). The bio-cathodes responded to nitrate addition on chronoamperometry through an increase of the reductive current. The denitrification efficiency of the pilots increased by 47% compared to the negative controls without electrodes after polarization. 16S rRNA gene sequencing of the biofilms and sediments evidenced the significant and discriminating presence of the Azoarcus and Pontibacter genera in the biofilms from biocathodes active for nitrate reduction. Our study shows the possibility to promote the development of efficient Azoarcus-dominated biocathodes from freshwater sediment to enhance nitrate removal from surface waters.

Exploring the Bacterial Communities of the Kaiafas Thermal Spring Anigrides Nymphes in Greece Prior to Rehabilitation Actions

Anigrides Nymphes of Lake Kaiafas is a thermal spring that is well known for its therapeutical properties, as the hot water (32-34 °C) is rich in sulfur compounds and minerals. Nowadays, efforts are made from the Hellenic Republic to modernize the existing facilities and infrastructure networks of the area. To study the complex ecosystem of the thermal spring, we collected water from four sampling points (Lake, and Caves 1, 2, and 3). Filtration method was used for microbial enumeration. In parallel, total bacterial DNA was extracted and subjected to next-generation sequencing (NGS). A total of 166 different bacterial families were detected. Differences in families, genera, and species abundances were detected between the different sampling points. Specifically, Comamonadaceae was the most common family detected in Lake and Cave 3. Similarly, in Caves 1 and 2, Rhodobacteraceae was detected at a higher percentage compared to the rest of the families. Moreover, the detection of sequences assigned to waterborne or opportunistic pathogens, i.e., Enterobacteriaceae, Legionellaceae, Coxiellaceae, and Clostridiaceae, as well as Enterococcus and Vibrio, is of great importance. Although the presence of pathogens was not examined by quantitative PCR, the detection of their sequences strengthens the need of the planned rehabilitation actions of this natural environment in order to allow human swimming.

Positive effects of zeolite powder on aerobic granulation: Nitrogen and phosphorus removal and insights into the interaction mechanisms

Aerobic granular sludge is considered one of the most promising biological wastewater treatment technologies of the 21st century. However, the long granulation time and poor treatment effect on N and P have severely limited its popularity and large-scale application. In this study, we systematically examine the strengthening effects of zeolite powder on granulation, N and P removal, and their interaction mechanisms. The addition of zeolite powder decreased sludge granulation time to 18 d, and improved average N and P removal rates by 4.48% and 2.22%, respectively. The multi-pore and nutrient-rich environment of the zeolite powder is beneficial for maintaining microbial activity and granular stability. Moreover, its adsorption to N and P enriches their respective removal strains, improving their removal efficiency.

Production and characterization of a bioactive extracellular homopolysaccharide produced by Haloferax sp. BKW301

The production of extracellular polysaccharides (EPS) by haloarchaeal members, with novel and unusual physicochemical properties, is of special importance and has the potential for extensive biotechnological exploitation. An extremely halophilic archaeon, Haloferax sp. BKW301 (GenBank Accession No. KT240044) isolated from a solar saltern of Baksal, West Bengal, India has been optimized for the production of EPS under batch culture. It produced a considerable amount (5.95 g/L) of EPS in the medium for halophiles with 15% NaCl, 3% glucose, 0.5% yeast extract, and 6% inoculum under shake flask culture at 120 rpm. The purified EPS, a homopolymer of galactose as revealed by chromatographic methods and Fourier-transform infrared spectroscopy, is noncrystalline (CI_xrd , 0.82), amorphous, and could emulsify hydrocarbons like kerosene, petrol, xylene, and so forth. Moreover, the polymer is highly thermostable (up to 420°C) and displayed pseudoplastic rheology. Biologically, the EPS was able to scavenge DPPH (2,2-diphenyl-1-picrylhydrazyl) radical efficiently and inhibit the proliferation of the Huh-7 cell line at an IC₅₀ value of 6.25 µg/ml with a Hill coefficient of 0.844. Large-scale production of this thermostable, pseudoplastic homopolysaccharide, therefore, could find suitable applications in industry and biotechnology.

Evolution of microbial community during dry storage and recovery of aerobic granular sludge

Aerobic granular sludge (AGS) was imbedded in agar and stored at 4 °C for 30 days, and then the stored granules were recovered in a sequencing batch reactor fed real wastewater within 11 days. Variations in microbial community compositions were investigated during dry storage and recovery of AGS, aiming to elucidate the mechanism of granular stability loss and recovery. The storage and recovery of AGS involved microbial community evolution. The dominant bacterial genera of the mature AGS were Zoogloea (relative abundance of 22.39%), Thauera (16.03%) and Clostridium_sensu_stricto (11.17%), and those of the stored granules were Acidovorax (26.79%), Macellibacteroides (12.83%) and Pseudoxanthomonas (5.69%), respectively. However, the dominant genera were Streptococcus (43.64%), Clostridium_sensu_stricto (12.3.6%) and Lactococcus (11.47%) in the recovered AGS. Methanogens were always the dominant archaeal species in mature AGS (93.01%), stored granules (99.99%) and the recovered AGS (94.84%). Facultative anaerobes and anaerobes proliferated and dominated in the stored granules, and their metabolic activities gradually led to granular structure destruction and property deterioration. However, the stored granules served as carriers for the microbes originated from the real septic tank wastewater during recovery. They proliferated rapidly and secreted a large number of extracellular polymeric substances which helped to recover the granular structure in 11 days.

Microbiomes and chemical components of feed water and membrane-attached biofilm in reverse osmosis system to treat membrane bioreactor effluents

Reverse osmosis (RO) system at a stage after membrane bioreactor (MBR) is used for the wastewater treatment and reclamation. One of the most serious problems in this system is membrane fouling caused by biofilm formation. Here, microbiomes and chemical components of the feed water and membrane-attached biofilm of RO system to treat MBR effluents were investigated by non-destructive confocal reflection microscopy, excitation-emission fluorescence spectroscopy and high-throughput sequencing of 16S rRNA genes. The microscopic visualization indicated that the biofilm contained large amounts of microbial cells (0.5 ± 0.3~3.9 ± 2.3 µm³/µm²) and the extracellular polysaccharides (3.3 ± 1.7~9.4 ± 5.1 µm³/µm²) and proteins (1.0 ± 0.2~1.3 ± 0.1 µm³/µm²). The spectroscopic analysis identified the humic and/or fulvic acid-like substances and protein-like substances as the main membrane foulants. High-throughput sequencing showed that Pseudomonas spp. and other heterotrophic bacteria dominated the feed water microbiomes. Meanwhile, the biofilm microbiomes were composed of diverse bacteria, among which operational taxonomic units related to the autotrophic Hydrogenophaga pseudoflava and Blastochloris viridis were abundant, accounting for up to 22.9 ± 4.1% and 3.1 ± 0.4% of the total, respectively. These results demonstrated that the minor autotrophic bacteria in the feed water played pivotal roles in the formation of polysaccharide- and protein-rich biofilm on RO membrane, thereby causing membrane fouling of RO system.

Ahniella affigens gen. nov., sp. nov., a gammaproteobacterium isolated from sandy soil near a stream

A bacterial strain, designated D13^T, was isolated from sandy soil near a stream in Sinan-gun, Republic of Korea. Cells were Gram-stain-negative, aerobic, non-motile and flexible rod-shaped. Growth occurred at 15-35 °C (optimum 30 °C) and pH 6.5-8.0 (pH 7.0). NaCl was not obligatory for growth but could be tolerated at up to 0.5 % (w/v) NaCl. The DNA G+C content of the genomic DNA of strain D13^T was 57.7 mol% and a phylogenetic analysis of the 16S rRNA gene sequence revealed that strain D13^T formed a distinct evolutionary lineage within the family Rhodanobacteraceae of the order Lysobacterales. Strain D13^T showed highest 16S rRNA sequence similarity to Lysobacter hankyongensis KTCe-2^T (92.7 %), followed by Luteimonas cucumeris Y4^T (92.7 %), Dyella japonica XD53^T (92.6 %) and Aquimonas voraii GPTSA 20^T (92.5 %). The major cellular fatty acids (>10 % of the total) were iso-C16 : 0, iso-C15 : 0 and summed feature 9 (iso-C17 : 1ω9с and/or C16 : 0 10-methyl). The respiratory quinone was ubiquinone-8 and the major polar lipids of the isolate consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylmonomethylethanolamine. Based on polyphasic analysis, strain D13^T could be differentiated from other genera in the family Rhodanobacteraceae, which suggests that strain D13^T represents a novel species of a new genus in the family Rhodanobacteraceae, for which the name Ahniella affigens gen. nov., sp. nov. is proposed. The type strain is D13^T (=KACC 19270^T=JCM 31634^T).

Microbiological studies of hot springs in India: a review

The earliest microbiological studies on hot springs in India date from 2003, a much later date compared to global attention in this striking field of study. As of today, 28 out of 400 geothermal springs have been explored following both culturable and non-culturable approaches. The temperatures and pH of the springs are 37-99 °C and 6.8-10, respectively. Several studies have been performed on the description of novel genera and species, characterization of different bio-resources, metagenomics of hot spring microbiome and whole genome analysis of few isolates. 17 strains representing novel species and many thermostable enzymes, including lipase, protease, chitinase, amylase, etc. with potential biotechnological applications have been reported by several authors. Influence of physico-chemical conditions, especially that of temperature, on shaping the hot spring microbiome has been established by metagenomic investigations. Bacteria are the predominant life forms in all the springs with an abundance of phyla Firmicutes, Proteobacteria, Actinobacteria, Thermi, Bacteroidetes, Deinococcus-Thermus and Chloroflexi. In this review, we have discussed the findings on all microbiological studies that have been carried out to date, on the 28 hot springs. Further, the possibilities of extrapolating these studies for practical applications and environmental impact assessment towards protection of natural ecosystem of hot springs have also been discussed.

Effect of the chemical composition of filter media on the microbial community in wastewater biofilms at different temperatures

This study investigates the microbial community composition in the biofilms grown on two different support media in fixed biofilm reactors for aerobic wastewater treatment, using next generation sequencing (NGS) technology. The chemical composition of the new type of support medium (TDR) was found to be quite different from the conventionally used support medium (stone). The analysis of 16S rRNA gene fragments recovered from the laboratory scale biofilm system show that biofilm support media and temperature conditions influence bacterial community structure and composition. Greater bacterial diversity was observed under each condition, primarily due to the large number of sequences available and sustenance of rare species. There were 6 phyla found, with the highest relative abundance shown by the phylum Proteobacteria (52.71%) followed by Bacteroidetes (33.33%), Actinobacteria (4.65%), Firmicutes, Verrucomicrobia (3.1%) and Chloroflex (>1%). The dataset showed 17 genera of bacterial populations to be commonly shared under all conditions, suggesting the presence of a core microbial community in the biofilms for wastewater treatment. However, some genera in the biofilms on TDR were observed in high proportions, which may be attributed to its chemical composition, explaining the improved level of wastewater treatment. The findings show that the structure of microbial communities in biofilm systems for wastewater treatment is affected by the properties of support matrix.

Process performance and bacterial community dynamics of partial-nitritation biofilters subjected to different concentrations of cysteine amino acid

Partial-nitritation processes are used for the biological treatment of high nitrogen-low organic carbon effluents, such as anaerobic digestion reject water. The release of certain products generated during the anaerobic digestion process, such as amino acids, could potentially reduce the performance of these partial-nitritation bioprocesses. To investigate this, four partial-nitritation biofilters were subjected to continuous addition of 0, 150, 300, and 500 mg L^-1 cysteine amino acid in their influents. The addition of the amino acid had an impact over the performance of the partial-nitritation process and the bacterial community dynamics of the systems analyzed. Ammonium oxidation efficiency decreased with the addition of the amino acid, and a net nitrogen elimination occurred in presence of cysteine through the operation period. Bacterial community dynamics showed a decrease of Nitrosomonas species and a proliferation of putative heterotrophs with nitrification capacity, such as Pseudomonas, or denitrification capacity, such as Denitrobacter or Alicycliphilus. The addition of cysteine irreversible affected the bioreactors, which could not achieve the performance obtained before the addition of the amino acid. A mathematical predictive equation of the process performance depending on cysteine concentration added and operational time under such concentration was developed. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1254-1263, 2016.

Microbacterium aureliae sp. nov., a novel actinobacterium isolated from Aurelia aurita, the moon jellyfish

The taxonomic position of a lemon-yellow-pigmented actinobacterium, strain JF-6T, isolated from Aurelia aurita, the moon jellyfish, collected from the Bay of Bengal coast, Kanyakumari, India, was determined using a polyphasic approach. The strain had phenotypic and chemotaxonomic properties that were consistent with its classification in the genus Microbacterium. Alignment of the 16S rRNA gene sequence of strain JF-6T with sequences from Microbacterium arthrosphaerae CC-VM-YT, Microbacterium yannicii G72T, Microbacterium trichothecenolyticum IFO 15077T, Microbacterium flavescens DSM 20643T, Microbacterium insulae DS-66T, Microbacterium resistens DMMZ 1710T and Microbacterium thalassium IFO 16060T revealed similarities of 98.95, 98.76, 98.43, 98.41, 98.41, 98.26 and 98.22 %, respectively. However, the levels of DNA-DNA relatedness with its closest phylogenetic neighbours confirmed that it represents a novel species within the genus. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and an unknown glycolipid. The major menaquinones detected for strain JF-6T were MK-13 and MK-12. The diamino acid in the cell-wall peptidoglycan was ornithine and the peptidoglycan was type B2β (Glu/Hyg-Gly-d-Orn). The DNA G+C content was 69.4 mol%. Based on these differences, strain JF-6T (=MTCC 11843T=JCM 30060T=KCTC 39828T) should be classified as the type strain of a novel species of Microbacterium, for which the name Microbacterium aureliae sp. nov. is proposed.

Denitratimonas tolerans gen. nov., sp. nov., a denitrifying bacterium isolated from a bioreactor for tannery wastewater treatment

A denitrifying bacterium, designated strain E4-1(T), was isolated from a bioreactor for tannery wastewater treatment, and its taxonomic position was investigated using a polyphasic approach. Strain E4-1(T), a facultative anaerobic bacterium, was observed to grow between 0 and 12 % (w/v) NaCl, between pH 3.0 and 12.0. Cells were found to be oxidase-positive and catalase-negative. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain E4-1(T) forms a distinct lineage with respect to closely related genera in the family Xanthomonadaceae, and is closely related to Chiayiivirga, Aquimonas and Dokdonella, and the levels of 16S rRNA gene sequence similarity with respect to the type species of related genera are less than 93.9 %. The predominant respiratory quinone was determined to be ubiquinone-8 (Q-8) and the major cellular fatty acids were determined to be iso-C15:0, iso-C17:1 ω9c, iso-C11:0 and iso-C11:0 3OH. Based on physiological, biochemical and chemotaxonomic properties together with results of comparative 16S rRNA gene sequence analysis, strain E4-1(T) is considered to represent a novel species in a new genus, for which the name Denitratimonas tolerans gen. nov., sp. nov. is proposed. The type strain is E4-1(T) (=KACC 17565(T) = NCAIM B 025327(T)).

Taxonomic description and genome sequence of Rheinheimera mesophila sp. nov., isolated from an industrial waste site

A novel Gram-staining-negative gammaproteobacterium, designated IITR-13T, was isolated from a pesticide-contaminated soil and characterized using a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, the strain showed the closest similarity (98.7 %) to Rheinheimera tangshanensis JA3-B52T followed by Rheinheimera texasensis A62-14BT (97.7 %) and Rheinheimera soli BD-d46T (97.3 %). The 16S rRNA gene sequence similarity of the novel strain to other members of the genus Rheinheimera was < 97.3 %. However, DNA–DNA hybridization between strain IITR-13T and the type strains of R. tangshanensis, R. texasensis and R. soli was 47.5 ± 0.6, 42.4 ± 0.4 and 39.8 ± 0.3 %, respectively; these values are less than 70 %, a threshold value for delineation of a novel species. The strain had C12 : 0 3-OH, C16 : 0, C17 : 1ω8c, summed feature 3 (C16 : 1ω6c/C16 : 1ω7c) and C18 : 1ω6c as the major fatty acids. The major isoprenoid quinones detected for strain IITR-13T were ubiquinone Q-8 and menaquinone MK-7.The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and seven unknown phospholipids. Based on phenotypic and chemotaxonomic characteristics and analysis of the 16S rRNA gene sequence, the novel strain should be assigned to a novel species, for which the name Rheinheimera mesophila sp. nov. is proposed, with the type strain IITR-13T ( = MTCC 12064T = DSM 29723T). Also, we report the draft genome sequence of Rheinheimera mesophila IITR-13T; the draft genome sequence includes 3 749 903 bases and comprises 3449 predicted coding sequences, with a G+C content of 47.8 %. It consists of 102 contigs (>1000 bp).

Mizugakiibacter sediminis gen. nov., sp. nov., isolated from a freshwater lake

A novel, moderately thermophilic, bacterial strain (skMP5T) was isolated from sediment of a freshwater lake in Japan. The cells were rod-shaped, motile and Gram-stain-negative. Growth was observed at temperatures ranging from 25 to 52 °C, with optimum growth observed at 48–50 °C. The pH range for growth was pH 5.0–8.2, with optimum growth at pH 6.0–7.0. The G+C content of genomic DNA was 72 mol%. The major components in the fatty acid profile were iso-C17 : 0 and iso-C17 : 1ω9c. The predominant isoprenoid quinone of the strain was ubiquinone Q-8. The strain was facultatively anaerobic, and reduced nitrate to nitrite under anoxic conditions. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate was a member of the family Xanthomonadaceae within the class Gammaproteobacteria , showing highest sequence similarity with Tahibacter aquaticus RaM5-2 (93.6 %) and Metallibacterium scheffleri DKE6T (93.3 %). On the basis of phylogenetic and phenotypic properties, strain skMP5T represents a novel species of a new genus, Mizugakiibacter sediminis gen. nov., sp. nov. The type strain of the type species is skMP5T ( = DSM 27098T = NBRC 109608T).

Chiayiivirga flava gen. nov., sp. nov., a novel bacterium of the family Xanthomonadaceae isolated from an agricultural soil, and emended description of the genus Dokdonella

A novel Gram-reaction-negative, yellow-pigmented, aerobic, non-motile and rod-shaped bacterium designated strain CC-YHH031T was isolated from an agricultural soil collected at Chiayi County, Taiwan. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CC-YHH031T formed a discrete monophyletic lineage in the family Xanthomonadaceae , sharing high pairwise sequence similarity of 93.5–95.2 and 94.8 % with species of the genus Dokdonella (94.9 % similarity to the type strain of the type species) and Aquimonas voraii GPTSA 20T, respectively. The genomic DNA G+C content of strain CC-YHH031T was 68.6±0.7 mol% and the predominant respiratory quinone was ubiquinone Q-8. Spermidine was the principal polyamine, with minor amounts of putrescine. Major fatty acids (>5 % of total fatty acids) were iso-C16 : 0, iso-C15 : 0, C16 : 1ω7c and/or C16 : 1ω6c (summed feature 3), iso-C17 : 1ω9c, iso-C14 : 0, iso-C11 : 0 and iso-C11 : 0 3-OH. The polar lipid profile of strain CC-YHH031T included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, two unidentified aminophospholipids (APL1–2) and four unidentified phospholipids (PL1–4). Strain CC-YHH031T was distinguished particularly from the type species of the genus Dokdonella ( Dokdonella koreensis ) by the presence of major amounts of iso-C14 : 0 and summed feature 3 and minor amounts of iso-C17 : 0 and by the complete absence of anteiso-C17 : 0, the presence of PL1–3 and APL1–2, the absence of APL3 and the presence of putrescine in the former. On the basis of distinguishing genotypic and phenotypic evidence, strain CC-YHH031T is proposed to represent a novel genus and species within the family Xanthomonadaceae , for which the name Chiayiivirga flava gen. nov., sp. nov. is proposed. The type strain of Chiayiivirga flava is CC-YHH031T ( = BCRC 80273T = DSM 24163T).

Planococcus plakortidis sp. nov., isolated from the marine sponge Plakortis simplex (Schulze)

A novel coccoid-shaped strain, AS/ASP6 (II)T, was isolated from a sample taken from Plakortis simplex (Schulze), a marine sponge, collected at a depth of 30 m from the Bay of Bengal. This strain was identified by using a polyphasic taxonomic approach. The results of 16S rRNA gene sequence analysis showed that strain AS/ASP6 (II)T should be assigned to the genus Planococcus . Chemotaxonomic data (A4α-type peptidoglycan; MK-6, MK-7 and MK-8 menaquinones; mainly branched cellular fatty acids; and phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol as cellular phospholipids) supported taxonomic placement in the genus Planococcus . Phylogenetic analysis of the 16S rRNA gene sequence showed that strain AS/ASP6 (II)T belonged to the genus Planococcus and was closely related to the type strains of Planococcus maritimus (99.1 %) followed by Planococcus rifietoensis (98.6 %), Planococcus maitriensis (98.5 %), Planococcus citreus (98.3 %), Planococcus salinarum (98.1 %), Planococcus columbae (97.9 %), Planococcus donghaensis (97.8 %) and Planococcus antarcticus (97.7 %); DNA–DNA hybridization values obtained were well below the threshold that is required for the proposal of a novel species. The G+C content of the genomic DNA was 51.0 mol%. The phenotypic and genotypic data showed that strain AS/ASP6 (II)T merits recognition as a representative of a novel species of the genus Planococcus , for which the name Planococcus plakortidis sp. nov. is proposed; the type strain is AS/ASP6 (II)T ( = MTCC 8491T = DSM 23997T).

Flavobacterium rakeshii sp. nov., isolated from marine sediment, and emended description of Flavobacterium beibuense Fu et al. 2011

A Gram-negative, non-motile bacterial strain that formed straight rods and straw yellow colonies, designated FCS-5(T), was isolated from a marine sediment from the Arabian Sea. The isolate exhibited most of the phenotypic properties expected for a member of the genus Flavobacterium. The major fatty acids were iso-C(15:0), iso-C(17:0) 3-OH, C(17:1)ω9c and summed feature 3 (comprising iso-C(15:0) 2-OH and/or C(16:1)ω7c). The only isoprenoid quinone was MK-6. The only polyamine was homospermidine and the major polar lipid was phosphatidylethanolamine. The G+C content of the genomic DNA was 32.4 mol%. According to 16S rRNA gene sequence analysis, strain FCS-5(T) belonged to the genus Flavobacterium and exhibited 99.3% 16S rRNA gene sequence similarity with Flavobacterium beibuense F44-8(T) and 90.9-94.6% sequence similarity with other members of the genus Flavobacterium. The results of physiological and biochemical tests allowed the discrimination of the isolate from its phylogenetic relatives. Strain FCS-5(T) is a representative of a novel species of the genus Flavobacterium, for which the name Flavobacterium rakeshii sp. nov. is proposed. The type strain is FCS-5(T) ( = MTCC 10967(T) = JCM 17928(T)). An emended description of F. beibuense is also proposed.

Exiguobacterium aquaticum sp. nov., a member of the genus Exiguobacterium

A Gram-positive, motile, short rod-shaped, orange pigmented bacterium, designated strain IMTB-3094(T), was isolated from a water sample collected from Tikkar Tal Lake, Haryana, and subjected to detailed polyphasic taxonomic analysis. Strain IMTB-3094(T) possessed most of the phenotypic and chemotaxonomic properties of the genus Exiguobacterium and, based on 16S rRNA gene sequence analysis, was assigned to this genus. Strain IMTB-3094(T) exhibited the highest 16S rRNA gene sequence similarity to Exiguobacterium mexicanum MTCC 7759(T) (99.5 %) followed by Exiguobacterium aurantiacum MTCC 6414(T) (99.1 %), Exiguobacterium aestuarii MTCC 7750(T) (98.0 %), Exiguobacterium profundum MTCC 10851(T) (98.0 %) and Exiguobacterium marinum MTCC 7751(T) (98.0 %). The G+C content of the genomic DNA of strain IMTB-3094(T) was 53.2 mol% and a DNA-DNA relatedness study confirmed that it represents a novel species. The major fatty acids of strain IMTB-3094(T) were iso-C(17 : 0) (16.1 %), anteiso-C(13 : 0) (19.0 %), iso-C(13 : 0) (11.9 %), iso-C(15 : 0) (9.8 %) and iso-C(17 : 1) (12.7 %). The predominant quinones were MK-7 (55.0 %) and MK-6 (26.0 %) with minor amounts of MK-8 (12.0 %). Based on phenotypic, chemotaxonomic and phylogenetic analyses, strain IMTB-3094(T) represents a novel species of the genus Exiguobacterium, for which the name Exiguobacterium aquaticum sp. nov. is proposed. The type strain is IMTB-3094(T) (= MTCC 10958(T) = JCM 17977(T)).

Fontibacillus aquaticus gen. nov., sp. nov., isolated from a warm spring

A novel facultatively anaerobic strain, designated GPTSA 19(T), was isolated from a warm spring and characterized using a polyphasic approach. The strain behaved as Gram-negative in the Gram staining procedure but showed a Gram-positive reaction in the aminopeptidase test. The novel strain was a mesophilic rod with ellipsoidal endospores. On the basis of 16S rRNA gene sequence analysis, the strain showed closest similarity (96.0 %) with Paenibacillus motobuensis MC10(T). The gene sequence similarity of the novel strain with other species of the genus Paenibacillus was <95.8 %. The novel strain also had PAEN 515F and 682F signature sequence stretches in the 16S rRNA gene that are usually found in most species of the genus Paenibacillus. The strain possessed anteiso-C(15 : 0) as the major fatty acid and MK-7 as the predominant menaquinone. Polar lipids included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), six unknown phospholipids (PLs), one aminophospholipid (PN), three glycolipids (GLs), two aminolipids (ALs), one aminophosphoglycolipid (APGL) and three unknown lipids (ULs). The polar lipid profile of the novel strain, especially as regards ALs, GLs and PLs, distinguished it from the recognized type species of the genus Paenibacillus, Paenibacillus polymyxa, as well as from its closest relative P. motobuensis. Based on phenotypic and chemotaxonomic characteristics and analysis of the 16S rRNA gene sequence, the new strain merits the rank of a novel genus for which the name Fontibacillus gen. nov. is proposed. The type species of the new genus is Fontibacillus aquaticus gen. nov., sp. nov. with the type strain GPTSA 19(T) (=MTCC 7155(T)=DSM 17643(T)).

Phylogenetic and metabolic bacterial diversity of Phragmites australis periphyton communities in two Hungarian soda ponds

Bacterial diversity of reed (Phragmites australis) periphyton communities of Kelemen-szék and Nagy-Vadas (two Hungarian soda ponds) was investigated using molecular cloning and cultivation-based techniques. The majority of the 80 Kelemen-szék and 72 Nagy-Vadas bacterial isolates proved to be moderately halophilic and alkaliphilic. A great proportion of the isolates showed phosphatase and urease activity, utilized aesculin, citrate and certain biopolymers (e.g., gelatine and tween 80). Partial 16S rDNA sequence analysis of 33 Kelemen-szék and 20 Nagy-Vadas ARDRA group representatives showed Gram-positive (Nesterenkonia, Cellulomonas, Dietzia, Bacillus and Planococcus) dominance at both sampling sites. Species of the genera Acidovorax, Hydrogenophaga (beta-Proteobacteria) and Flavobacterium, Sphingobacterium (Bacteroidetes) were represented only from Kelemen-szék. Altogether 16 isolates showed low sequence similarity with yet described bacteria and may represent novel taxa. Screening of the 16S rRNA gene libraries of 129 Kelemen-szék and 158 Nagy-Vadas clones resulted in 30 and 28 different ARDRA groups, respectively. Sequence analysis revealed a Gram-negative (Rheinheimera, Aquimonas, Cellvibrio, Flavobacterium and Sphingobacterium) dominated phylogenetic diversity. A high number of the clones were affiliated with uncultured bacterial clones described from diverse environmental samples.

Tetrasphaera remsis sp. nov., isolated from the Regenerative Enclosed Life Support Module Simulator (REMS) air system

Two Gram-positive, coccoid, non-spore-forming bacteria (strains 3-M5-R-4(T) and 3-M5-R-7), cells of which formed diploid, tetrad and cluster arrangements, were isolated from air of the Regenerative Enclosed Life Support Module Simulator system. On the basis of 16S rRNA gene sequence similarity, these strains were shown to belong to the family Intrasporangiaceae and were related to members of the genus Tetrasphaera, with similarities to the seven known species of the genus Tetrasphaera of 96.71-97.76 %. The fatty acid profile supported affiliation of these novel isolates to the genus Tetrasphaera, although larger amounts of octadecanoic acid (C(18 : 0)) and cis-9-octadecenoic acid (C(18 : 1)) were observed in the isolates, thus enabling them to be differentiated from other Tetrasphaera species. In addition, DNA-DNA hybridization studies indicated that these strains belonged to a novel species that could be readily distinguished from its nearest neighbour, Tetrasphaera japonica DSM 13192(T), which had less than 20 % DNA-DNA relatedness. Physiological and biochemical tests showed few phenotypic differences, but genotypic analysis enabled these gelatin-liquefying strains to be differentiated from the seven Tetrasphaera species. The strains described in this study therefore represent a novel species, for which the name Tetrasphaera remsis sp. nov. is proposed; the type strain is 3-M5-R-4(T) (=ATCC BAA-1496(T) =CIP 109413(T)).

Aspromonas composti gen. nov., sp. nov., a novel member of the family Xanthomonadaceae

Two novel bacteria, strains TR7-09T and P2-12-1, were isolated from samples of compost and river sediment, respectively. The strains comprised Gram-negative, motile, non-spore-forming rods, produced creamy white colonies on R2A agar, contained Q-8 as the predominant ubiquinone, contained iso-15 : 0, iso-17 : 0ω9c and iso-11 : 0 3-OH as the major fatty acids, and had polar lipid profiles consisting of phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol and an unknown phospholipid. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strains were most closely related to Thermomonas haemolytica DSM 13605T, Silanimonas lenta KCTC 12236T and Xanthomonas campestris LMG 568T (with 92.5, 92.0 and 92.0 % sequence similarity, respectively) and formed a separate lineage within the family Xanthomonadaceae. The combined genotypic and phenotypic data supported the conclusion that the strains represent a novel genus and species, for which the name Aspromonas composti gen. nov., sp. nov. is proposed. The type strain is TR7-09T (=KCTC 12666T=DSM 18010T).

Arenimonas donghaensis gen. nov., sp. nov., isolated from seashore sand

A Gram-negative, aerobic bacterium, designated strain HO3-R19T, which was isolated from seashore sand in Pohang city, Korea, was characterized on the basis of a polyphasic taxonomic approach. Phylogenetic analyses of 16S rRNA gene sequences revealed that strain HO3-R19T represents a new lineage within the Gammaproteobacteria; sequence similarities between strain HO3-R19T and members of other related genera were less than 93.5 %. Strain HO3-R19T was also distinguished from related genera based on differences in several phenotypic characteristics. Cells were straight or slightly curved rods and formed white colonies on R2A agar. The major isoprenoid quinone was ubiquinone 8 (Q-8), and predominant cellular fatty acids were iso-C16 : 0, iso-C15 : 0 and iso-C17 : 1 ω9c. The DNA G+C content of strain HO3-R19T was 65.0 mol%. Based on physiological, biochemical and chemotaxonomic traits together with results of comparative 16S rRNA sequence analysis, strain HO3-R19T is considered to represent a novel species in a new genus, for which the name Arenimonas donghaensis gen. nov., sp. nov. is proposed. The type strain of Arenimonas donghaensis is HO3-R19T (=KACC 11381T=DSM 18148T).

First reported infections caused by three newly described genera in the family Xanthomonadaceae

Members of the family of Xanthomonadaceae are typically characterized as environmental organisms. With the exception of Stenotrophomonas maltophilia, these organisms are infrequently implicated as human pathogens. We describe three cases of central venous catheter-associated bloodstream infections caused by Dokdonella koreensis, Aquimonas voraii, and a Luteibacter sp., all newly named genera within the family Xanthomonadaceae. The three patients all had histories of underlying hematological disorders, presented with fever, and recovered fully following treatment. These isolates required 16S rRNA gene sequencing for identification and, unlike S. maltophilia, demonstrated susceptibility to most antibiotics tested. This report represents the first description of human infections caused by these organisms.

Flavobacterium indicum sp. nov., isolated from warm spring water in Assam, India

A polyphasic taxonomic approach was employed to characterize a strain designated GPTSA100-9T, which was isolated from water sampled from a warm spring. The micro-organism, comprising Gram-negative, strictly aerobic rods, could not grow on nutritionally rich media such as tryptic soy broth. Analysis of the 16S rRNA gene sequence (1396 nt) of strain GPTSA100-9Trevealed that it is a member of the genusFlavobacterium, sharing 99.8 % sequence similarity with the CFB group bacterium strain A0653 (AF236016), 93.4 % with ‘[Flexibacter]aurantiacussubsp.excathedrus’ and 93.2–92.0 % withFlavobacterium saliperosum,Flavobacterium soli,Flavobacterium aquatileandFlavobacterium columnare. The G+C content of the genomic DNA was 31.0 mol%. The major fatty acids of the strain grown on modified R2A agar were iso-C15 : 0(18.5 %), iso-C15 : 1G (18.0 %), summed feature 3 (iso-C15 : 02-OH and/or C16 : 1ω7c, 16.6 %) and iso-C17 : 03-OH (9.0 %). On the basis of phenotypic and genotypic characteristics, strain GPTSA100-9Trepresents a novel species of the genusFlavobacterium, for which the nameFlavobacterium indicumsp. nov. is proposed. The type strain is GPTSA100-9T(=MTCC 6936T=DSM 17447T).

Aeromonas sharmana sp. nov., isolated from a warm spring

A Gram-negative, facultatively anaerobic bacterial strain designated GPTSA-6(T) was isolated from a water sample collected from a warm spring in Assam, India. Preliminary analysis of the 16S rRNA gene sequence of this isolate revealed its affiliation to the family Aeromonadaceae. Detailed characterization using a polyphasic approach indicated that strain GPTSA-6(T) is most closely related to Aeromonas sobria but differs significantly from existing members of the genus Aeromonas. Analysis of the almost-complete (1430 nt) 16S rRNA gene sequence of this strain revealed that its closest relative (99.23 % similarity) is an uncultured bacterial clone, A-8, isolated from an algal bloom. Of the taxa with validly published names, Aeromonas sobria ATCC 43979(T) showed the highest level of sequence similarity (95.13 %) with respect to strain GPTSA-6(T), followed by Aeromonas molluscorum 848T(T) and Aeromonas popoffii LMG 17541(T) (95.04 % similarity in both cases). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, it can be concluded that strain GPTSA-6(T) represents a novel species of the genus Aeromonas, for which the name Aeromonas sharmana sp. nov. is proposed. The type strain is GPTSA-6(T) (=MTCC 7090(T)=DSM 17445(T)).

Emticicia oligotrophica gen. nov., sp. nov., a new member of the family 'Flexibacteraceae', phylum Bacteroidetes

An aquatic bacterium, strain GPTSA100-15T, was isolated on nutritionally poor medium TSBA100 (tryptic soy broth diluted 100 times and solidified with 1.5 % agarose) and characterized using a polyphasic approach. The isolate was unable to grow on commonly used nutritionally rich media such as tryptic soy agar, nutrient agar and Luria-Bertani agar. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was affiliated with the family 'Flexibacteraceae' in the phylum Bacteroidetes. Phylogenetically, it showed closest similarity (94.0 %) with an uncultured bacterial clone, HP1A92, detected in a sludge microbial community. Among the culturable bacteria, the isolate had highest 16S rRNA gene sequence similarity with Leadbetterella byssophila 4M15T (87.8 %). Sequence similarities with other members of the phylum Bacteroidetes were less than 85 %. The fatty acid profile of the isolate grown on TSBA100 indicated that the major fatty acid was iso-C15:0, which is also present in many members of the family 'Flexibacteraceae'. Cells of strain GPTSA100-15T are Gram-negative, strictly aerobic rods. The DNA G+C content of the isolate is 36.9 mol%. Results of phenotypic, chemotaxonomic and phylogenetic analyses clearly indicate that strain GPTSA100-15T represents a new genus within the family 'Flexibacteraceae'; the name Emticicia gen. nov. is proposed for the genus, with Emticicia oligotrophica sp. nov. as the type species. The type strain of Emticicia oligotrophica is GPTSA100-15T (=MTCC 6937T=DSM 17448T).

Agrococcus lahaulensis sp. nov., isolated from a cold desert of the Indian Himalayas

The taxonomic position of a lemon-yellow-pigmented actinobacterium, strain K22-21T, isolated from a soil sample from Lahaul-Spiti Valley in the Indian Himalayas, was determined using a polyphasic approach. The strain had phenotypic and chemical properties that were consistent with its classification in the genusAgrococcus. Alignment of the 16S rRNA gene sequence of strain K22-21Twith sequences fromAgrococcus jenensisDSM 9580T,Agrococcus baldriDSM 14215TandAgrococcus citreusDSM 12453Trevealed similarities of 98.5, 96.8 and 96.6 %, respectively. However, the level of DNA–DNA relatedness between strain K22-21TandA. jenensiswas 55.1 %. The novel strain could be distinguished from type strains of the three species of the genusAgrococcususing DNA–DNA relatedness and phenotypic data. Based on these differences, strain K22-21T(=MTCC 7154T=DSM 17612T) should be classified as the type strain of a novel species ofAgrococcus, for which the nameAgrococcus lahaulensissp. nov. is proposed.