Novosphingobium lindaniclasticum sp. nov., a hexachlorocyclohexane (HCH)-degrading bacterium isolated from an HCH dumpsite

Characterization of anaerobic biotransformation of hexachlorocyclohexanes by novel microbial consortia enriched from channel and river sediments

The microbial biotransformation of hexachlorocyclohexane (HCH) by novel anaerobic microbial consortia enriched from sediments of an industrial effluent channel and the river Ravi in Pakistan was examined. The anaerobic consortia were capable of biotransforming α-, β-, γ-, and δ-HCH through reductive dichloroelimination, resulting in the formation of benzene and monochlorobenzene. Concerning γ-HCH biotransformation by the channel and river cultures, isotopic fractionations for carbon (εC) were - 5.3 ± 0.4 (‰) and - 10.6 ± 1.2 (‰), while isotopic fractionations for chlorine (εCl) were - 4.4 ± 0.4 (‰) and - 7.8 ± 0.9 (‰), respectively. Furthermore, lambda values (Λ), representing the correlation of δ13C and δ37Cl fractionation, were determined to be 1.1 ± 0.1 and 1.3 ± 0.1 for γ-HCH biotransformation, suggesting a reductive dichloroelimination as the initial step of HCH biotransformation in both cultures. Amplicon sequencing targeting the 16S rRNA genes revealed that Desulfomicrobium populations were considerably increased in both cultures, indicating their possible involvement in the degradation process. These findings suggest that Desulfomicrobium-like populations may have an important role in biotransformation of HCH and novel anaerobic HCH-degrading microbial consortia could be useful bioaugmentation agents for the bioremediation of HCH-contaminated sites in Pakistan.

Novel insights into aerobic 17β-estradiol degradation by enriched microbial communities from mangrove sediments

Various persistent organic pollutants (POPs) including estrogens are often enriched in mangrove regions. This research investigated the estrogens pollution levels in six mangroves located in the Southern China. The estrogen levels were found to be in the range of 5.3-24.9 ng/g dry weight, suggesting that these mangroves had been seriously contaminated. The bacterial communities under estrogen stress were further enriched by supplementing 17β-estradiol (E2) as the sole carbon source. The enriched bacterial communities showed an excellent E2 degradation capacity > 95 %. These communities were able to transform E2 into estrone (E1), 4-hydroxy-estrone, and keto-estrone, etc. 16 S rDNA sequencing and metagenomics analysis revealed that bacterial taxa Oleiagrimonas, Pseudomonas, Terrimonas, and Nitratireductor etc. were the main contributors to estrogen degradation. Moreover, the genes involved in E2 degradation were enriched in the microbial communities, including the genes encoding 17β-hydroxysteroid dehydrogenase, estrone 4-hydroxylase, etc. Finally, the analyses of functional genes and binning genomes demonstrated that E2 was degraded by bacterial communities via dehydrogenation into E1 by 17β-hydroxysteroid dehydrogenase. E1 was then catabolically converted to 3aα-H-4α(3'-propanoate)- 7aβ-methylhexahydro-1,5-indanedione via 4,5-seco pathway. Alternatively, E1 could also be hydroxylated to keto-estrone, followed by B-ring cleavage. This study provides novel insights into the biodegradation of E2 by the bacterial communities in estrogen-contaminated mangroves.

Genomic and physiological characterization of Novosphingobium terrae sp. nov., an alphaproteobacterium isolated from Cerrado soil containing a mega-sized chromid

A novel bacterial strain, designated GeG2T, was isolated from soils of the native Cerrado, a highly biodiverse savanna-like Brazilian biome. 16S rRNA gene analysis of GeG2T revealed high sequence identity (100%) to the alphaproteobacterium Novosphingobium rosa; however, comparisons with N. rosa DSM 7285T showed several distinctive features, prompting a full characterization of the new strain in terms of physiology, morphology, and, ultimately, its genome. GeG2T cells were Gram-stain-negative bacilli, facultatively anaerobic, motile, positive for catalase and oxidase activities, and starch hydrolysis. Strain GeG2T presented planktonic-sessile dimorphism and cell aggregates surrounded by extracellular matrix and nanometric spherical structures were observed, suggesting the production of exopolysaccharides (EPS) and outer membrane vesicles (OMVs). Despite high 16S rDNA identity, strain GeG2T showed 90.38% average nucleotide identity and 42.60% digital DNA-DNA hybridization identity with N. rosa, below species threshold. Whole-genome assembly revealed four circular replicons: a 4.1 Mb chromosome, a 2.7 Mb extrachromosomal megareplicon, and two plasmids (212.7 and 68.6 kb). The megareplicon contains a few core genes and plasmid-type replication/maintenance systems, consistent with its classification as a chromid. Genome annotation shows a vast repertoire of carbohydrate-active enzymes and genes involved in the degradation of aromatic compounds, highlighting the biotechnological potential of the new isolate. Chemotaxonomic features, including polar lipid and fatty acid profiles, as well as physiological, molecular, and whole-genome comparisons showed significant differences between strain GeG2T and N. rosa, indicating that it represents a novel species, for which the name Novosphingobium terrae is proposed. The type strain is GeG2T (= CBMAI 2313T = CBAS 753 T).

HCH Removal in a Biochar-Amended Biofilter

This study evaluated the efficiency of two biofilter systems, with and without biochar chambers installed, at degrading and removing HCH and its isomers in natural drainage water. The biochar biofilter proved to be 96% efficient at cleaning HCH and its transformation products from drainage water, a significant improvement over classic biofilter that remove, on average, 68% of HCH. Although iron- and sulfur-oxidizing bacteria, such as Gallionella and Sulfuricurvum, were dominant in the biochar bed outflows, they were absent in sediments, which were rich in Simplicispira, Rhodoluna, Rhodoferax, and Flavobacterium. The presence of functional genes involved in the biodegradation of HCH isomers and their byproducts was confirmed in both systems. The high effectiveness of the biochar biofilter displayed in this study should further encourage the use of biochar in water treatment solutions, e.g., for temporary water purification installations during the construction of other long-term wastewater treatment technologies, or even as final solutions at contaminated sites.

Post-reclamation microbial diversity and functions in hexachlorocyclohexane (HCH) contaminated soil in relation to spontaneous HCH tolerant vegetation

The toxicity, volatility and persistence of the obsolete organochlorine pesticide hexachlorocyclohexane (HCH), makes reclamation of contaminated areas a priority for the health and welfare of neighboring human communities. Microbial diversity and functions and their relation to spontaneous vegetation in post-excavation situations, are essential indicators to consider in bioaugmentation or microbe-assisted phytoremediation strategies at field scale. Our study aimed to evaluate the effects of long-term HCH contamination on soil and plant-associated microbial communities, and whether contaminated soil has the potential to act as a bacterial inoculum in post-excavation bioremediation strategies. To scrutinize the role of vegetation, the potential nitrogen fixation of free-living and symbiotic diazotrophs of the legume Lotus tenuis was assessed as a measure of nutrient cycling functions in soil under HCH contamination. Potential nitrogen fixation was generally not affected by HCH, with the exception of lower nifH gene counts in excavated contaminated rhizospheres, most probably a short-term HCH effect on early bacterial succession in this compartment. HCH shaped microbial communities in long-term contaminated bulk soil, where we identified possible HCH tolerants such as Sphingomonas and Altererythrobacter. In L. tenuis rhizosphere, microbial community composition was additionally influenced by plant growth stage. Sphingobium and Massilia were the bacterial genera characteristic for HCH contaminated rhizospheres. Long-term HCH contamination negatively affected L. tenuis growth and development. However, root-associated bacterial community composition was driven solely by plant age, with negligible HCH effect. Results showed that L. tenuis acquired possible HCH tolerant bacteria such as the Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade, Sphingomonas, Massilia or Pantoea which could simultaneously offer plant growth promoting (PGP) benefits for the host. Finally, we identified an inoculum with possibly HCH tolerant, PGP bacteria transferred from the contaminated bulk soil to L. tenuis roots through the rhizosphere compartment, consisting of Mesorhizobium loti, Neorhizobium galegae, Novosphingobium lindaniclasticum, Pantoea agglomerans and Lysobacter bugurensis.

Dual C-Cl Isotope Analysis for Characterizing the Reductive Dechlorination of α- and γ-Hexachlorocyclohexane by Two Dehalococcoides mccartyi Strains and an Enrichment Culture

Hexachlorocyclohexanes (HCHs) are persistent organic contaminants that threaten human health. Microbial reductive dehalogenation is one of the most important attenuation processes in contaminated environments. This study investigated carbon and chlorine isotope fractionation of α- and γ-HCH during the reductive dehalogenation by three anaerobic cultures. The presence of tetrachlorocyclohexene (TeCCH) indicated that reductive dichloroelimination was the first step of bond cleavage. Isotope enrichment factors (ε_C and ε_Cl) were derived from the transformation of γ-HCH (ε_C, from -4.0 ± 0.5 to -4.4 ± 0.6 ‰; ε_Cl, from -2.9 ± 0.4 to -3.3 ± 0.4 ‰) and α-HCH (ε_C, from -2.4 ± 0.2 to -3.0 ± 0.4 ‰; ε_Cl, from -1.4 ± 0.3 to -1.8 ± 0.2 ‰). During α-HCH transformation, no enantioselectivity was observed, and similar ε_c values were obtained for both enantiomers. The correlation of ¹³C and ³⁷Cl fractionation (Λ = Δδ¹³C/Δδ³⁷Cl ≈ ε_C/ε_Cl) of γ-HCH (from 1.1 ± 0.3 to 1.2 ± 0.1) indicates similar bond cleavage during the reductive dichloroelimination by the three cultures, similar to α-HCH (1.7 ± 0.2 to 2.0 ± 0.3). The different isotope fractionation patterns during reductive dichloroelimination and dehydrochlorination indicates that dual-element stable isotope analysis can potentially be used to evaluate HCH transformation pathways at contaminated field sites.

Analysis of 1,000+ Type-Strain Genomes Substantially Improves Taxonomic Classification of Alphaproteobacteria

The class Alphaproteobacteria is comprised of a diverse assemblage of Gram-negative bacteria that includes organisms of varying morphologies, physiologies and habitat preferences many of which are of clinical and ecological importance. Alphaproteobacteria classification has proved to be difficult, not least when taxonomic decisions rested heavily on a limited number of phenotypic features and interpretation of poorly resolved 16S rRNA gene trees. Despite progress in recent years regarding the classification of bacteria assigned to the class, there remains a need to further clarify taxonomic relationships. Here, draft genome sequences of a collection of genomes of more than 1000 Alphaproteobacteria and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa recognized as problematic long ago but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera and of a variety of genera to other families. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which are confirmed as valuable taxonomic markers. Similarly, analysis of the gene content was shown to provide valuable taxonomic insights in the class. Significant incongruities between 16S rRNA gene and whole genome trees were not found in the class. The incongruities that became obvious when comparing the results of the present study with existing classifications appeared to be caused mainly by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. Another probable cause of misclassifications in the past is the partially low overall fit of phenotypic characters to the sequence-based tree. Even though a significant degree of phylogenetic conservation was detected in all characters investigated, the overall fit to the tree varied considerably.

Comparative Genomics of Degradative Novosphingobium Strains With Special Reference to Microcystin-Degrading Novosphingobium sp. THN1

Bacteria in genus Novosphingobium associated with biodegradation of substrates are prevalent in environments such as lakes, soil, sea, wood and sediments. To better understand the characteristics linked to their wide distribution and metabolic versatility, we report the whole genome sequence of Novosphingobium sp. THN1, a microcystin-degrading strain previously isolated by Jiang et al. (2011) from cyanobacteria-blooming water samples from Lake Taihu, China. We performed a genomic comparison analysis of Novosphingobium sp. THN1 with 21 other degradative Novosphingobium strains downloaded from GenBank. Phylogenetic trees were constructed using 16S rRNA genes, core genes, protein-coding sequences, and average nucleotide identity of whole genomes. Orthologous protein analysis showed that the 22 genomes contained 674 core genes and each strain contained a high proportion of distributed genes that are shared by a subset of strains. Inspection of their genomic plasticity revealed a high number of insertion sequence elements and genomic islands that were distributed on both chromosomes and plasmids. We also compared the predicted functional profiles of the Novosphingobium protein-coding genes. The flexible genes and all protein-coding genes produced the same heatmap clusters. The COG annotations were used to generate a dendrogram correlated with the compounds degraded. Furthermore, the metabolic profiles predicted from KEGG pathways showed that the majority of genes involved in central carbon metabolism, nitrogen, phosphate, sulfate metabolism, energy metabolism and cell mobility (above 62.5%) are located on chromosomes. Whereas, a great many of genes involved in degradation pathways (21-50%) are located on plasmids. The abundance and distribution of aromatics-degradative mono- and dioxygenases varied among 22 Novosphingoibum strains. Comparative analysis of the microcystin-degrading mlr gene cluster provided evidence for horizontal acquisition of this cluster. The Novosphingobium sp. THN1 genome sequence contained all the functional genes crucial for microcystin degradation and the mlr gene cluster shared high sequence similarity (≥85%) with the sequences of other microcystin-degrading genera isolated from cyanobacteria-blooming water. Our results indicate that Novosphingobium species have high genomic and functional plasticity, rearranging their genomes according to environment variations and shaping their metabolic profiles by the substrates they are exposed to, to better adapt to their environments.

Novosphingobium clariflavum sp. nov., isolated from a household product plant

A Gram-stain-negative, rod-shaped, bright-yellow-pigmented bacterium, designated 164T, was isolated from a used sponge for equipment cleaning at a household product plant in China. The 16S rRNA gene sequence comparisons indicated that strain 164T was most closely related to Novosphingobium panipatense DSM 22890T (98.28 % similarity) and shared sequence similarities of 97.73-98.27 % with other members of the genus Novosphingobium. In DNA-DNA hybridization studies the relatedness between strain 164T and its closest phylogenetic neighbours was <70 %, which indicated that strain 164T represented a novel species of the genus Novosphingobium. The DNA G+C content of strain 164T was 65.9 mol%. The major respiratory quinone was ubiquinone Q-10 (83.5 %) with minor amounts of Q-9 (16.5 %). The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, sphingoglycolipid, phosphatidylcholine, unidentified aminolipids and unidentified aminophospholipids. Spermidine was the major polyamine. The major fatty acids were summed feature 8 (consisting of C18 : 1ω7c and/or C18 : 1ω6c) and C14 : 0 2-OH. The results obtained from phylogenetic analysis, DNA-DNA hybridization, and chemotaxonomic and phenotypic analysis support the conclusion that strain 164T represents a novel species of the genus Novosphingobium, for which the name Novosphingobium clariflavum sp. nov. is proposed. The type strain is 164T (=CICC 11035sT=DSM 103351T).

Comparative Genomic Analysis Reveals Habitat-Specific Genes and Regulatory Hubs within the Genus Novosphingobium

This study highlights the significant role of the genetic repertoire of a microorganism in the similarity between Novosphingobium strains. The results suggest that the phylogenetic relationships were mostly influenced by metabolic trait enrichment, which is possibly governed by the microenvironment of each microbe’s respective niche. Using core genome analysis, the enrichment of a certain set of genes specific to a particular habitat was determined, which provided insights on the influence of habitat on the distribution of metabolic traits for Novosphingobium strains. We also identified habitat-specific protein hubs, which suggested delineation of Novosphingobium strains based on their habitat. Examining the available genomes of ecologically diverse bacterial species and analyzing the habitat-specific genes are useful for understanding the distribution and evolution of functional and phylogenetic diversity in the genus Novosphingobium.

Species belonging to the genus Novosphingobium are found in many different habitats and have been identified as metabolically versatile. Through comparative genomic analysis, we identified habitat-specific genes and regulatory hubs that could determine habitat selection for Novosphingobium spp. Genomes from 27 Novosphingobium strains isolated from diverse habitats such as rhizosphere soil, plant surfaces, heavily contaminated soils, and marine and freshwater environments were analyzed. Genome size and coding potential were widely variable, differing significantly between habitats. Phylogenetic relationships between strains were less likely to describe functional genotype similarity than the habitat from which they were isolated. In this study, strains (19 out of 27) with a recorded habitat of isolation, and at least 3 representative strains per habitat, comprised four ecological groups—rhizosphere, contaminated soil, marine, and freshwater. Sulfur acquisition and metabolism were the only core genomic traits to differ significantly in proportion between these ecological groups; for example, alkane sulfonate (ssuABCD) assimilation was found exclusively in all of the rhizospheric isolates. When we examined osmolytic regulation in Novosphingobium spp. through ectoine biosynthesis, which was assumed to be marine habitat specific, we found that it was also present in isolates from contaminated soil, suggesting its relevance beyond the marine system. Novosphingobium strains were also found to harbor a wide variety of mono- and dioxygenases, responsible for the metabolism of several aromatic compounds, suggesting their potential to act as degraders of a variety of xenobiotic compounds. Protein-protein interaction analysis revealed β-barrel outer membrane proteins as habitat-specific hubs in each of the four habitats—freshwater (Saro_1868), marine water (PP1Y_AT17644), rhizosphere (PMI02_00367), and soil (V474_17210). These outer membrane proteins could play a key role in habitat demarcation and extend our understanding of the metabolic versatility of the Novosphingobium species.

IMPORTANCE This study highlights the significant role of a microorganism’s genetic repertoire in structuring the similarity between Novosphingobium strains. The results suggest that the phylogenetic relationships were mostly influenced by metabolic trait enrichment, which is possibly governed by the microenvironment of each microbe’s respective niche. Using core genome analysis, the enrichment of a certain set of genes specific to a particular habitat was determined, which provided insights on the influence of habitat on the distribution of metabolic traits in Novosphingobium strains. We also identified habitat-specific protein hubs, which suggested delineation of Novosphingobium strains based on their habitat. Examining the available genomes of ecologically diverse bacterial species and analyzing the habitat-specific genes are useful for understanding the distribution and evolution of functional and phylogenetic diversity in the genus Novosphingobium.

Novosphingobium guangzhouense sp. nov., with the ability to degrade 1-methylphenanthrene

A novel Gram-stain-negative, flagellated, rod-shaped, yellow-pigmented aerobic bacterium, strain SA925T, that is capable of degrading 1-methylphenanthrene was isolated from oil-polluted soil collected from a refinery located in Guangzhou, China. Phylogenetic analysis based on the 16S rRNA gene sequence demonstrated that strain SA925T belongs to the genus Novosphingobium and is evolutionarily close to the type strains of Novosphingobium gossypii (98.5 % similarity), Novosphingobium panipatense (98.2 %), Novosphingobium mathurense (98.0 %) and Novosphingobium pentaromativorans (96.5 %). The G+C content of the genomic DNA was 60.2 mol%. DNA-DNA hybridization experiments between strain SA925T and the closest strain, Novosphingobium gossypii JM-1396T, revealed a low level of relatedness (35.5 %). Strain SA925T grew at 10-35 °C, at pH 6.0-8.0 and in the presence of 0-4 % (w/v) NaCl. The major fatty acids were C18 : 1ω7c, C16 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The polar lipid profiles mainly consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylethanolamine and sphingoglycolipid (the characteristic polar lipid). The predominant ubiquinone was Q-10. The major polyamine was spermidine. Based on the phylogenetic, phenotypic and physiological characteristics, strain SA925T was considered to represent a novel species of the genus Novosphingobium, for which the name Novosphingobium guangzhouense sp. nov. is proposed. The type strain is SA925T (=DSM 32207T=GDMCC 1.1110T).

Novosphingobium profundi sp. nov. isolated from a deep-sea seamount

A marine bacterial strain, F72^T, was isolated from a solitary scleractinian coral, collected in Yap seamounts in the Pacific Ocean. Strain F72^T is a Gram-negative, light-yellow-pigmented, motile, rod-shaped bacterium. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain F72^T is related to the genus Novosphingobium and has high 16S rRNA gene sequence similarities with the type strains of Novosphingobium pentaromativorans US6-1^T (97.7 %), Novosphingobium panipatense SM16^T (97.6 %), Novosphingobium mathurense SM117^T (97.2 %) and Novosphingobium barchaimii LL02^T (97.1 %). Ubiquinone Q-10 was detected as the dominant quinone. The predominant cellular fatty acids were C_18:1ω7c and C_17:1ω6c. The genomic DNA G+C content of strain F72^T was 63.4 mol %. The polar lipids profile contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylcholine, sphingoglycolipid and one uncharacterized lipid. Strain F72^T shared DNA relatedness of 25 % with N. pentaromativorans JCM 12182^T, 31 % with N. panipatense DSM 22890^T, 21 % with N. mathurense DSM 23374^T and 26 % with N. barchaimii DSM 25411^T. Combined data from phenotypic, phylogenetic and DNA-DNA relatedness studies demonstrated that the strain F72^T is a representative of a novel species of the genus Novosphingobium, for which we propose the name Novosphingobium profundi sp. nov. (type strain F72^T = KACC 18566^T = CGMCC 1.15390^T).

Novosphingobium gossypii sp. nov., isolated from Gossypium hirsutum

A Gram-stain-negative, rod-shaped, non-spore-forming bacterium (strain JM-1396T) producing a yellow pigment, was isolated from the healthy internal stem tissue of post-harvest cotton (Gossypium hirsutum, cultivar ‘DES-119’) grown at the Plant Breeding Unit at the E. V. Smith Research Center in Tallassee (Macon county), AL, USA. 16S rRNA gene sequence analysis of strain JM-1396T showed high sequence similarity values to the type strains of Novosphingobium mathurense, Novosphingobium panipatense (both 98.6 %) and Novosphingobium barchaimii (98.5 %); sequence similarities to all other type strains of species of the genus Novosphingobium were below 98.3 %. DNA–DNA pairing experiments of the DNA of strain JM-1396T and N. mathurense SM117T, N. panipatense SM16T and N. barchaimii DSM 25411T showed low relatedness values of 8 % (reciprocal 7 %), 24 % (reciprocal 26 %) and 19 % (reciprocal 25 %), respectively. Ubiquinone Q-10 was detected as the dominant quinone; the fatty acids C18 : 1ω7c (71.0 %) and the typical 2-hydroxy fatty acid, C14 : 0 2-OH (11.7 %), were detected as typical components. The polar lipid profile contained the diagnostic lipids diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid and phosphatidylcholine. The polyamine pattern contained the major compound spermidine and only minor amounts of other polyamines. All these data revealed that strain JM-1396T represents a novel species of the genus Novosphingobium. For this reason we propose the name Novosphingobium gossypii sp. nov. with the type strain JM-1396T ( = LMG 28605T = CCM 8569T = CIP 110884T).

Impacts of dimethyl phthalate on the bacterial community and functions in black soils

Dimethyl phthalate (DMP), a known endocrine disruptor and one of the phthalate esters (PAEs), is a ubiquitous pollutant. Its impacts on living organisms have aroused great concern. In this study, the impacts of DMP contamination on bacterial communities and functions were tested by using microcosm model in black soils. The results showed that the operational taxonomic unit (OTUs) richness and bacterial diversity were reduced by DMP contamination. The relative percentages of some genera associated with nitrogen metabolism were increased by DMP contamination, while the relative percentages of some other genera that were extremely beneficial to soil health were decreased by DMP contamination. Further, the relative percentages of some genera that possessed the capability to degrade DMP were increased by the DMP treatment at low concentrations (5, 10, and 20 mg/kg), but were decreased by the high concentration DMP treatment (40 mg/kg). Clearly, DMP contamination changed the bacterial community structure and disturbed the metabolic activity and functional diversity of the microbes in black soils. Our results suggest that DMP pollution can alter the metabolism and biodiversity of black soil microorganisms, thereby directly impact fertility and ecosystem functions.

N ovosphingobium fluoreni sp. nov., isolated from rice seeds

A yellow-pigmented, Gram-stain-negative, rod-shaped, non-spore-forming bacterium designated strain HLJ-RS18T, which could degrade fluorene, was isolated from rice seeds collected from Heilongjiang Province, China. Similarities of full-length of 16S rRNA gene sequences between strain HJL-RS18T and the type strains of the genus Novosphingobium with validly published names ranged from 93.8 to 97.1 %. Phylogenetic analysis with maximum-likelihood and neighbour-joining methods revealed that strain HLJ-RS18T belonged to genus Novosphingobium and strain HLJ-RS18T formed a distinct clade to Novosphingobium chloroacetimidivorans BUT-14T (96.9 % similarity based on 16S rRNA gene). DNA–DNA hybridization of HLJ-RS18T and BUT-14T showed a low relatedness value of 22.4±0.9 %, which indicated that strain HLJ-RS18T represents a novel species of the genus Novosphingobium . The genomic DNA G+C content of strain HLJ-RS18T was 62 mol%. Ubiquinone Q-10 was the major respiratory quinone. Spermidine was the predominant polyamine. Polar lipids consisted mainly of aminophospholipid, phosphatidylglycerol, phosphatidylethanolamine, phospholipid and sphingoglycolipid. The predominant fatty acid composition of HLJ-RS18T were summed 8 (C18 : 1ω7c and/or C18 : 1ω6c, 61.5 %), C16 : 0 (14.2 %), summed 3 (C16 : 1ω7c and/or C16 : 1ω6c, 13.5 %) and C14 : 0 2-OH (6.8 %). Phylogenetic analysis, DNA–DNA hybridization, chemotaxonomic data and phenotypic characteristics support the conclusion that HLJ-RS18T represents a novel species within the genus Novosphingobium . Therefore, we propose the species Novosphingobium fluoreni sp. nov. with HLJ-RS18T ( = DSM 27568T = ACCC19180T) as the type strain.

Bioremediation using Novosphingobium strain DY4 for 2,4-dichlorophenoxyacetic acid-contaminated soil and impact on microbial community structure

The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is commonly used for weed control. The ubiquity of 2,4-D has gained increasing environmental concerns. Biodegradation is an attractive way to clean up 2,4-D in contaminated soil. However, information on the bioaugmentation trial for remediating contaminated soil is still very limited. The impact of bioaugmentation using 2,4-D-degraders on soil microbial community remains unknown. The present study investigated the bioremediation potential of a novel degrader (strain DY4) for heavily 2,4-D-polluted soil and its bioaugmentation impact on microbial community structure. The strain DY4 was classified as a Novosphingobium species within class Alphaproteobacteria and harbored 2,4-D-degrading TfdAα gene. More than 50 and 95 % of the herbicide could be dissipated in bioaugmented soil (amended with 200 mg/kg 2,4-D) respectively in 3-4 and 5-7 days after inoculation of Novosphingobium strain DY4. A significant growth of the strain DY4 was observed in bioaugmented soil with the biodegradation of 2,4-D. Moreover, herbicide application significantly altered soil bacterial community structure but bioaumentation using the strain DY4 showed a relatively weak impact.

Proposal of Novosphingobium rhizosphaerae sp. nov., isolated from the rhizosphere

A yellow, Gram-stain-negative, rod-shaped, non-spore-forming bacterium (strain JM-1T) was isolated from the rhizosphere of a field-grown Zea mays plant in Auburn, AL, USA. 16S rRNA gene sequence analysis of strain JM-1T showed high sequence similarity to the type strains of Novosphingobium capsulatum (98.9 %), Novosphingobium aromaticivorans (97.4 %), Novosphingobium subterraneum (97.3 %) and Novosphingobium taihuense (97.1 %); sequence similarities to all other type strains of species of the genus Novosphingobium were below 97.0 %. DNA–DNA hybridizations of strain JM-1T and N. capsulatum DSM 30196T, N. aromaticivorans SMCC F199T and N. subterraneum SMCC B0478T showed low similarity values of 33 % (reciprocal: 21 %), 14 % (reciprocal 16 %) and 36 % (reciprocal 38 %), respectively. Ubiquinone Q-10 was detected as the major respiratory quinone. The predominant fatty acid was C18 : 1ω7c (71.0 %) and the typical 2-hydroxy fatty acid C14 : 0 2-OH (11.7 %) was detected. The polar lipid profile contained the diagnostic lipids diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid and phosphatidylcholine. Characterization by 16S rRNA gene sequence analysis, physiological parameters, pigment analysis, and ubiquinone, polar lipid and fatty acid composition revealed that strain JM-1T represents a novel species of the genus Novosphingobium . For this species we propose the name Novosphingobium rhizosphaerae sp. nov. with the type strain JM-1T ( = LMG 28479T = CCM 8547T).

Novosphingobium kunmingense sp. nov., isolated from a phosphate mine

A yellow-pigmented, Gram-stain-negative, strictly aerobic, rod-shaped, round-ended bacterium, designated strain 18-11HKT, was isolated from a phosphate mine situated in the suburb of Kunming in Yunnan province in south-western China. The taxonomic status of this strain was evaluated by using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity, strain 18-11HKT was shown to belong to the genus Novosphingobium , showing the highest levels of sequence similarity with respect to ‘Novosphingobium ginsenosidimutans’ FW-6 (97.2 %), Novosphingobium subterraneum DSM 12447T (96.7 %), Novosphingobium aromaticivorans DSM 12444T (96.7 %) and Novosphingobium tardaugens DSM 16702T (96.3 %). Strain 18-11HKT had a genomic DNA G+C content of 65.3 mol% and Q-10 as the predominant respiratory quinone. DNA–DNA hybridizations of strain 18-11HKT with N. subterraneum DSM 12447T, N. aromaticivorans DSM 12444T and N. tardaugens DSM 16702T showed low relatedness values of 29.6, 33.5 and 32.3 %, respectively. The predominant fatty acids of strain 18-11HKT were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0, and the major 2-hydroxy fatty acid was C14 : 0 2-OH. The polar lipid profile revealed the presence of sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and some unidentified lipids. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain 18-11HKT represents a novel species of the genus Novosphingobium , for which the name Novosphingobium kunmingense sp. nov. is proposed. The type strain is 18-11HKT ( = CGMCC 1.12274T = DSM 25975T).

Novosphingobium malaysiense sp. nov. isolated from mangrove sediment

A novel bacterium, strain MUSC 273(T), was isolated from mangrove sediments of the Tanjung Lumpur river in the state of Pahang in peninsular Malaysia. The bacterium was yellow-pigmented, Gram-negative, rod-shaped and non-spore-forming. The taxonomy of strain MUSC 273(T) was studied by a polyphasic approach and the organism showed a range of phenotypic and chemotaxonomic properties consistent with those of the genus Novosphingobium. The 16S rRNA gene sequence of strain MUSC 273(T) showed the highest sequence similarity to those of Novosphingobium indicum H25(T) (96.8 %), N. naphthalenivorans TUT562(T) (96.4 %) and N. soli CC-TPE-1(T) (95.9 %) and lower sequence similarity to members of all other species of the genus Novosphingobium. Furthermore, in phylogenetic analyses based on the 16S rRNA gene sequence, strain MUSC 273(T) formed a distinct cluster with members of the genus Novosphingobium. DNA-DNA relatedness of strain MUSC 273(T) to the type strains of the most closely related species, N. indicum MCCC 1A01080(T) and N. naphthalenivorans DSM 18518(T), was 29.2 % (reciprocal 31.0 %) and 17 % (reciprocal 18 %), respectively. The major respiratory quinone was ubiquinone Q-10, the major polyamine was spermidine and the DNA G+C content was 63.3±0.1 mol%. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine and sphingoglycolipid. The major fatty acids were C18 : 1ω7c, C17 : 1ω6c, C16 : 0, C15 : 0 2-OH and C16 : 1ω7c. Comparison of BOX-PCR fingerprints indicated that strain MUSC 273(T) represented a unique DNA profile. The combined genotypic and phenotypic data showed that strain MUSC 273(T) represents a novel species of the genus Novosphingobium, for which the name Novosphingobium malaysiense sp. nov. is proposed. The type strain is MUSC 273(T) ( = DSM 27798(T) = MCCC 1A00645(T) = NBRC 109947(T)).

Devosia lucknowensis sp. nov., a bacterium isolated from hexachlorocyclohexane (HCH) contaminated pond soil

Strain L15(T), a Gram-negative, motile, orange colored bacterium was isolated from pond soil in the surrounding area of a hexachlorocyclohexane (HCH) dump site at Ummari village in Lucknow, India. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain L15(T) belongs to the family Hyphomicrobiaceae in the order Rhizobiales. Strain L15(T) showed highest 16S rRNA gene sequence similarity to Devosia chinhatensis IPL18(T) (98.0%). Chemotaxonomic data revealed that the major fatty acids were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c), C18:1 ω7c 11-methyl, C16:0 and C18:0. The major polar lipids of strain L15(T) were diphosphatidylglycerol and phosphatidylglycerol. The genomic DNA G+C content of strain L15(T) was 59.8%. Polyamine profile showed the presence of sym-homospermidine with traces of putrescine. Ubiquinone Q-10 was the major respiratory quinone present. Based on these data, strain L15(T) (=CCM 7977(T) =DSM 25398(T)) was classified as a type strain of a novel species, for which the name Devosia lucknowensis sp. nov. is proposed.

Genome Sequence of Novosphingobium lindaniclasticum LE124T, Isolated from a Hexachlorocyclohexane Dumpsite

Novosphingobium lindaniclasticum LE124^T is a hexachlorocyclohexane (HCH)-degrading bacterium isolated from a high-dosage-point HCH dumpsite (450 mg HCH/g soil) located in Lucknow, India (27°00′N and 81°09′E). Here, we present the annotated draft genome sequence of strain LE124^T, which has an estimated size of 4.86 Mb and is comprised of 4,566 coding sequences.