Marinobacter denitrificans sp. nov., isolated from marine sediment of southern Scott Coast, Antarctica.

A novel bacterium, designated JB02H27T, was isolated from marine sediment collected from the southern Scott Coast, Antarctica. Cells were Gram-stain-negative, facultatively anaerobic, polar-flagellated and motile rods. Growth occurred at 4-45 °C, at pH 7.0-9.0 and with 3-25 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain JB02H27T consistently fell within the genus Marinobacter and formed a clade together with Marinobacter algicola DG893T (98.8 % similarity), Marinobacter confluentis KCTC 42705T (98.4 %), Marinobacter salarius R9SW1T (98.4%) and Marinobacter halotolerans CP12T (97.9 %), which were subsequently used as reference strains for comparisons of phenotypic and chemotaxonomic characteristics. Average nucleotide identity values between strain JB02H27T and the four related type strains were 80.9, 76.6, 81.9 and 76.3 %, respectively. The major fatty acids were summed feature 3, C16 : 0, C18 : 1 ω9c and C16 : 0 N alcohol. The polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and an unidentified phospholipid, aminolipid, aminophospholipid and glycolipids. The sole respiratory quinone was ubiquinone-9. The DNA G+C content was 56.9 mol%. Based on the genomic, phylogenetic, phenotypic and chemotaxonomic analysis, we propose that strain JB02H27T represents a novel species of the genus Marinobacter, for which the name Marinobacter denitrificans sp. nov. is proposed. The type strain is JB02H27T (=GDMCC 1.1528T=KCTC 62941T).

Sphingobium paulinellae and Sphingobium algicola Lee and Jeon 2017 are two later heterotypic synonyms of Sphingobium limneticum Chen et al. 2013 and emended description of the species.

Phylogenetic analysis of the genus Sphingobium had shown that the type strains of Sphingobium paulinellae, Sphingobium algicola and Sphingobium limneticum shared a very close relationship between each other. The 16S rRNA gene sequences similarity values between each other ranged from 99.65 to 99.93 %. Whole genome sequencing was performed and genomic relatedness values between each pair of the species were 97.49-100 % (ANI) and 79.3-100 % (dDDH), respectively, all higher than the threshold values of 95-96 % ANI and 70 % dDDH suggested for species discrimination, and implicated that the type strains should belong to the same species of the genus Sphingobium. The phenotypic and chemotaxonomic characterizations performed in the original descriptions of S. paulinellae and S. algicola also supported the same conclusion. Due to priority of publication Sphingobium paulinellae and Sphingobium algicola Lee and Jeon 2017, should be taken as two later heterotypic synonyms of Sphingobium limneticum Chen et al. 2013. Correspondingly, the species description of Sphingobium limneticum was emended based on this study.

Pseudidiomarina gelatinasegens sp. nov., isolated from surface sediment of the Terra Nova Bay, Antarctica.

Polyphasic taxonomic analysis was performed to characterize a novel bacterium, which was isolated from surface sediment of the Terra Nova Bay, Antarctica, and designated as R04H25T. The cells of the isolate were Gram-stain-negative, aerobic, non-motile, slightly curved rods. Growth occurred at 4-42 °C, pH 7.0-9.5, and in 1-15 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences indicated that strain R04H25T formed an independent lineage within the genus Pseudidiomarina and its nearest neighbours were Pseudidiomarina donghaiensis 908033T (98.2 %), Pseudidiomarina marina PIM1T (98.1 %), Pseudidiomarina woesei W11T (97.8 %), Pseudidiomarina maritima 908087T (97.1 %) and Pseudidiomarina tainanensis PIN1T (97.0 %). The average nucleotide identities between strain R04H25T and the nearest neighbours were 76.2-77.7 %. The major fatty acids were iso-C17 : 0, summed feature 9, iso-C15 : 0, C16 : 0 and iso-C11 : 0 3-OH. The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminophospholipid, three unidentified glycolipids and two unidentified lipids. The predominant respiratory quinone was ubiquinone 8. The genomic DNA G+C content was 48.2 mol%. On the basis of the phylogenetic, physiological and chemotaxonomic results, we propose a novel species named as Pseudidiomarina gelatinasegens sp. nov. in the genus Pseudidiomarina, with the type strain R04H25T (=GDMCC 1.1503T=KCTC 62911T).

Culture-Dependent and -Independent Analyses Reveal the Diversity, Structure, and Assembly Mechanism of Benthic Bacterial Community in the Ross Sea, Antarctica.

The benthic bacterial community in Antarctic continental shelf ecosystems are not well-documented. We collected 13 surface sediments from the Ross Sea, a biological hotspot in high-latitude maritime Antarctica undergoing rapid climate change and possible microflora shift, and aimed to study the diversity, structure and assembly mechanism of benthic bacterial community using both culture-dependent and -independent approaches. High-throughput sequencing of 16S rRNA gene amplicons revealed 370 OTUs distributed in 21 phyla and 284 genera. The bacterial community was dominated by Bacteroidetes, Gamma- and Alphaproteobacteria, and constituted by a compact, conserved and positively-correlated group of anaerobes and other competitive aerobic chemoheterotrophs. Null-model test based on ßNTI and RCBray indicated that stochastic processes, including dispersal limitation and undominated fractions, were the main forces driving community assembly. On the other hand, environmental factors, mainly temperature, organic matter and chlorophyll, were significantly correlated with bacterial richness, diversity and community structure. Moreover, metabolic and physiological features of the prokaryotic taxa were mapped to evaluate the adaptive mechanisms and functional composition of the benthic bacterial community. Our study is helpful to understand the structural and functional aspects, as well as the ecological and biogeochemical role of the benthic bacterial community in the Ross Sea.

Pseudidiomarina maritima Wu et al. 2009 is a later heterotypic synonym of Pseudidiomarina tainanensis Jean et al. 2009 and emended description of the species.

A comparative analysis of the two type strains of Pseudidiomarina maritima 908087T and Pseudidiomarina tainanensis PIN1T was performed to examine their taxonomic relationship. The 16S rRNA gene sequence of P. maritima 908087T shared a high similarity (99.8 %) with that of P. tainanensis PIN1T. The phylogenetic trees based on 16S rRNA gene sequences indicated that the two strains formed a tight cluster within the genus Pseudidiomarina. Whole genomic comparison between the two strains revealed a digital DNA-DNA hybridization estimate of 75.8 % and an average nucleotide identity value of 97.3 %, strongly indicating that they represented a single species. In addition, the strains did not display any striking differences in their metabolic, physiological or chemotaxonomic features. Therefore, we propose that Pseudidiomarina maritima is a later heterotypic synonym of Pseudidiomarina tainanensis.

Ramlibacter humi sp. nov., isolated from tropical forest soil.

A Gram-stain-negative, aerobic and non-motile strain, designated 18x22-1T, was isolated from a forest soil sample collected from Limushan Nature Reserve in Hainan Province, PR China. Growth occurred at 15-37 °C and pH 6.0-8.0 without NaCl. The 16S rRNA gene sequence analyses showed that strain 18x22-1T was closely related to Ramlibacter tataouinensis DSM 14655T (98.5 %), followed by Ramlibacter henchirensis DSM 14656T (97.9 %) and other Ramlibacter species and formed a stable cluster with R. tataouinensis DSM 14655T, R. henchirensis DSM 14656T, Ramlibacter solisilvae JCM 19319T and Ramlibacter rhizophilus CCTCC AB 2015357T. Results of chemotaxonomic analyses showed that ubiquinone-8 (Q-8) was the major respiratory quinone, and the major fatty acids (>10 % of the total amounts) were C16 : 0 and C17 : 0cyclo. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminopholipids and four unidentified phospholipids. The draft genome sequence was 4.47 Mb long with a G+C content of 68.9 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain 18x22-1T and four closely related type strains were in the range of 79.3-82.3 % and 21.9-25.1 %, respectively. The results of phenotypic, phylogenetic and chemotaxonomic analyses supported that strain 18x22-1T represents a novel species of the genus Ramlibacter, for which the name Ramlibacterhumi sp. nov. is proposed. The type strain is 18x22-1T (=GDMCC 1.1584T=KCTC 52922T).

Diaphorobacter polyhydroxybutyrativorans Qiu et al. 2015 is a later heterotypic synonym of Diaphorobacter nitroreducens Khan and Hiraishi 2003.

Comparative analyses of Diaphorobacter polyhydroxybutyrativorans SL-205T and Diaphorobacter nitroreducens NA10BT were conducted for clarifying their taxonomic relationship. The sequences of the 16S rRNA gene and nine housekeeping genes of SL-205T and NA10BT shared high similarities, above 98.8 %. Whole-genomic comparison between the two strains revealed a digital DNA-DNA hybridization estimate of 85.1 % and an average nucleotide identity of 98.3 % that were well above respective recognized thresholds for bacterial species delineation, strongly indicating that they represent the same genomospecies. The metabolic, physiological and chemotaxonomic features of SL-205T were also shown to be congruent with those of NA10BT. Therefore, we conclude that Diaphorobacter polyhydroxybutyrativoransQiu et al. 2015 is a later heterotypic synonym of Diaphorobacter nitroreducens Khan and Hiraishi 2003.

Chakrabartia godavariana gen. nov., sp. nov., a novel member of the family Sphingomonadaceae isolated from the Godavari River, India.

A Gram-stain-negative, aerobic, yellow-pigmented, oxidase-positive and rod-shaped bacterium, designated PRB40T, was isolated from the Godavari River in India during the course of 'Kumbh Mela', the world's largest mass gathering event. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain PRB40T formed a lineage within the family Sphingomonadaceae and was distinct from the most closely related genera Sphingorhabdus, Novosphingobiumand Sphingomonas with sequence similarity values ≤95.2 %. Growth of strain PRB40T occurred at 10-40 °C (optimum 30 °C), at pH 6.0-9.0 (pH 7.0) and with 0-0.5 % (w/v) NaCl concentration (0 %). The major respiratory quinone was ubiquinone-10 (Q-10). It contained C17 : 1ω6c, C14 : 0 2-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) as the major cellular fatty acids. The predominant polar lipids were phospholipid, phosphatidylethanolamine and sphingoglycolipid. It took sym-homospermidine as the major polyamine. The DNA G+C content based on its draft genome sequence was 63.7 mol%. The polyphasic taxonomic analyses indicated that strain PRB40T represents a novel species of a novel genus within the family Sphingomonadaceae, for which the name Chakrabartia godavariana gen. nov., sp. nov. is proposed. The type strain of Chakrabartia godavariana is PRB40T (=MCC 3406T=GDMCC 1.1197T=KCTC 52678T=LMG 29985T).

Whole genome sequences reveal the presence of 11 heterotypic synonyms in the genus Sphingobium and emended descriptions of Sphingobium indicum, Sphingobium fuliginis, Sphingobium xenophagum and Sphingobium cupriresistens.

Phylogenetic analysis based on 16S rRNA gene sequences of the genus Sphingobium showed the presence of four distinguishable clusters, in each of which the species shared almost the same evolutionary distance. They were Sphingobium indicum, Sphinogbium lucknowense, Sphinogbium chinhatense, Sphinogbium francense and Sphinogbium japonicum in cluster I, Sphinogbium barthaii and Sphinogbium fuliginis in cluster II, Sphinogbium hydrophobicum and Sphinogbium xenophagum in cluster III and Sphinogbium czechense and Sphinogbium cupriresistens in cluster IV. The 16S rRNA gene sequence similarities between the species in each cluster were all higher than 98 %. Genome-based average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) relatedness values between the species of each cluster were all higher than the threshold values of 95-96 % ANI and 70 % dDDH for species discrimination, respectively, suggesting that each cluster represents only one species of the genus Sphingobium. Due to priority of publication, S. lucknowense, S. chinhatense, S. francense and S. japonicum should be taken as later heterotypic synonyms of S. indicum, S. barthaii as a later heterotypic synonym of S. fuliginis, S. hydrophobicum as a later heterotypic synonym of S. xenophagum and S. czechense as a later heterotypic synonym of S. cupriresistens. Correspondingly, the descriptions of S. indicum, S. fuliginis, S. xenophagum and S. cupriresistens are also emended based on this study.

Hymenobacter metallilatus sp. nov., isolated from abandoned lead-zinc ore.

An aerobic, non-motile, Gram-stain-negative, red-to-pinkish and rod-shaped bacterium, designated 9PBR-2T, was isolated from an abandoned lead-zinc ore sample collected from Meizhou, Guangdong Province, PR China. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 9PBR-2T belongs to the genus Hymenobacter and was most closely related to Hymenobacter rigui KCTC 12533T (98.0 %), Hymenobacter swuensis KCTC 32018T (97.8 %) and Hymenobacter perfusus LMG 26000T (97.6 %). The calculated average nucleotide identity values based on whole genome sequences between strain 9PBR-2T and closely related type strains ranged from 81.3 to 84.1 %. Correspondingly, the digital DNA-DNA hybridization values ranged from 25.5 to 28.1 %. The major fatty acids of strain 9PBR-2T were iso-C15:0, anteiso-C15:0, C16:1ω5c, summed feature 3 (C16:1ω6c and/or C16:1ω7c) and summed feature 4 (iso-C17:1 I and/or anteiso-C17:1 B). It contained menaquinone 7 (MK-7) as the major isoprenoid quinone and phosphatidylethanolamine as the major polar lipid. The genomic DNA G+C content based on whole genome sequence was 59.8 mol%. Characterization based on phylogenetic, chemotaxonomic and phenotypic analyses clearly indicated that strain 9PBR-2T represents a novel species of the genus Hymenobacter, for which the name Hymenobactermetallilatus sp. nov. is proposed. The type strain is 9PBR-2T (=GDMCC 1.1492T=JCM 32699T).

Sphingomonas lenta sp. nov., a slowly growing bacterium isolated from an abandoned lead-zinc mine.

A novel slowly growing member of the genus Sphingomonas, designated 1PNM-20T, was isolated from an abandoned lead-zinc mine in Meizhou, Guangdong Province, PR China. A polyphasic taxonomic study was performed to characterize the novel strain. Growth occurred on Reasoner's 2A (R2A) agar and peptone-yeast extract (PYE) agar, but not in liquid R2A or PYE media. Cells were Gram-stain-negative, aerobic, non-spore-forming, rod-shaped and motile with a polar flagellum (monotrichous). 16S rRNA gene sequence comparison showed that it shared the highest similarity with Sphingomonas carriPR0302T (97.2 %), followed by Sphingomonas spermidinifaciens 9NM-10T (97.0 %), Sphingomonas floccifaciens FQM01T (97.0 %) and other species of Sphingomonas (<97 %). Phylogenetic analyses clearly showed that strain 1PNM-20T fell into the cluster of Sphingomonas, and was most closely related to S. carri. The draft genome sequence was 3.76 Mb in length with a DNA G+C content of 69.8 mol%. Major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and 11-methyl C18 : 1ω7c, with C14 : 0 2-OH as the main hydroxy fatty acid. Ubiquinone 10 (Q-10) was the predominant respiratory quinone, and sym-homospermidine was displayed as the major polyamine. The polar lipids were composed of sphingoglycolipid, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, an unidentified phospholipid and an unidentified glycolipid. The phenotypic, phylogenetic and chemotaxonomic results supported the hypothesis that strain 1PNM-20T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas lenta sp. nov. is proposed. The type strain is 1PNM-20T (=GDMCC 1.660T=DSM 27572T).

Chitinophaga flava sp. nov., isolated from monsoon evergreen broad-leaved forest soil.

A Gram-stain-negative, aerobic, non-motile strain, K3CV102501T, was isolated from a soil sample collected from the monsoon evergreen broad-leaved forest of Dinghushan Biosphere Reserve located in Guangdong Province, PR China. The primal colony of strain K3CV102501T was very similar to the fruiting body of myxobacteria on the original isolation plates. Young cultures of strain K3CV102501T contained long (2-4×0.4-0.5 µm) filamentous cells and divided into rod shapes (0.7-1.0×0.6-0.8 µm) after 4 days of incubation at 28 °C. Strain K3CV102501T grew at pH 6.0-9.5 (optimum, pH 6.5-7.5) and 7-42 °C (optimum, 28-35 °C). Phylogenetic analysis based on its 16S rRNA gene sequence showed that strain K3CV102501T belonged to the genus Chitinophagaand showed the highest similarity to C.hitinophaga jiangningensis JCM 19354T (96.9 %). The DNA G+C content of the type strain was 46.6 mol%. The major fatty acids (>10 %) were iso-C15 : 0, C16 : 1ω5c and iso-C17 : 0 3-OH. The major polar lipids were phosphatidylethanolamine and an unidentified aminolipid. Menaquinone-7 was the predominant quinone. The phenotypic, chemotaxonomic and phylogenetic data clearly showed that strain K3CV102501T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga flava sp. nov. is proposed. The type strain is K3CV102501T (=KCTC 62435T=GDMCC 1.1325T).

Microvirga flavescens sp. nov., a novel bacterium isolated from forest soil and emended description of the genus Microvirga.

An aerobic, Gram-stain-negative, motile and rod-shaped bacterium, designated c27j1T, was isolated from a forest soil sample from the Chebaling National Nature Reserve in Guangdong Province, China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain c27j1T belongs to the genus Microvirga and was most closely related to Microvirga aerophila DSM 21344T (97.7 %) and Microvirga subterranea DSM 14364T (96.7 %). The average nucleotide identity and digital DNA-DNA hybridization values based on whole genome sequences of strain c27j1 T and M. aerophila DSM 21344T were 77.2 and 22.4 %, respectively. It contained ubiquinone 10 as the predominant quinone, and C19 : 0 cycloω8c and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) as the major fatty acids. The polar lipids consisted of phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, phosphatidylethanolamine and two unidentified glycolipids. The genomic DNA G+C content based on the whole genome sequence was 62.2 mol%. Phenotypic, chemotaxonomic, phylogenetic and genomic analyses suggested that strain c27j1T should represent a novel species of the genus Microvirga, for which the name Microvirgaflavescens sp. nov. is proposed. The type strain is c27j1T (=GDMCC 1.1356T=KCTC 62433T). The description of the genus Microvirga is also emended, including the major fatty acids, genome size and DNA G+C content.

Lysobacter silvisoli sp. nov., isolated from forest soil.

A yellow-pigmented, Gram-stain-negative, gliding and rod-shaped bacterial strain, designated zong2l5T, was isolated from a forest soil sample at Dinghu Mountain, Guangdong Province, PR China. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain zong2l5T belongs to the genus Lysobacter, and was most closely related to Lysobacter enzymogenes KCTC 12131T (97.7 %) and Lysobacter soli KCTC 22011T (97.6 %). The novel strain showed an average nucleotide identity (ANI) value of 81.5 % and a digital DNA-DNA hybridization (dDDH) value of 25.3 % with L. enzymogenes KCTC 12131T based on draft genome sequences, followed by L. soli KCTC 22011T with ANI and dDDH values of 79.4 % and 22.7 %, respectively. The DNA G+C content of strain zong2l5T based on the whole genome sequence was 69.2 mol%. The major fatty acids were iso-C15 : 0, iso-C17 : 0 and summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0). Strain zong2l5T contained Q-8 as the major isoprenoid quinone and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl-N-methylethanolamine, phosphatidylethanolamine, three unidentified phospholipids and an unidentified aminolipid. The phenotypic, genotypic and chemotaxonomic anlyses clearly showed that strain zong2l5T represents a novel species of the genus Lysobacter, for which the name Lysobactersilvisoli sp. nov. is proposed. The type strain is zong2l5T (=GDMCC 1.1489T=KCTC 52923T).

Chitinophaga varians sp. nov., isolated from forest soil.

A Gram-stain-negative, aerobic, non-motile bacterium, designated strain 10-7W-9003T, was isolated from the forest soil of Limushan National Forest Park, south-east China (19° 10' 42″ N, 109° 44' 45″ E). Strain 10-7W-9003T showed a shape change during the course of culture from long filamentous cells (5-10×0.4-0.5 µm) at 5-36 h, to rod shaped (1.0-1.5×0.5-0.7 µm) with inoculation after 2 days. It grew optimally at 28-30 °C and pH 6.5-7.5. On the basis of 16S rRNA gene sequence analysis, it belongs to the genus Chitinophaga and is most closely related to Chitinophaga eiseniae KACC 13774T and Chitinophaga qingshengii JCM 30026T, with 16S rRNA gene sequences similarities of 98.8 and 98.3 %, respectively. However, the DNA-DNA hybridization study showed that strain 10-7W-9003T shared relatively low relatedness values with KACC 13774T (21.8 %) and JCM 30026T (20.4 %), respectively. The major fatty acids (>10 %) were iso-C15 : 0, C16 : 1ω5c and iso-C17 : 0 3-OH. The genomic DNA G+C content was 50.7 mol%. It contained MK-7 as the major quinone. The phenotypic, chemotaxonomic and phylogenetic data clearly showed that strain 10-7W-9003T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga varians sp. nov. is proposed. The type strain is 10-7W-9003T (=GDMCC 1.1252T=KACC 19415T=KCTC 52926T).

Subsaxibacter sediminis sp. nov., isolated from Arctic glacial sediment and emended description of the genus Subsaxibacter.

A Gram-stain-negative, yellowish-orange pigmented, rod-shaped, motile bacterium, designated strain ARC111T, was isolated from sediment of Arctic permafrost at Midtre Lovénbreen glacier, Svalbard. 16S rRNA gene based identification of strain ARC111T demonstrated highest sequence similarities to Subsaxibacter broadyi P7T (97.8 %) and Subsaxibacter arcticus JCM30334T (97.5 %) and ≤95.2 % with all other members of the family Flavobacteriaceae. Phylogenetic analysis revealed the distinct positioning of strain ARC111T within the genus Subsaxibacter. The G+C content of ARC111T was 37.8±0.5 mol% while DNA-DNA hybridization depicted 35.6 % relatedness with S. arcticus JCM30334T. Strain ARC111T had C15 : 0iso, C16 : 0iso 3-OH, C15 : 1iso G, C15 : 0anteiso, C16 : 1iso H and C17 : 0iso 3-OH as major (>5 % of the total) cellular fatty acids and MK-6 was the predominant respiratory quinone. The polar lipid profile of strain ARC111T consisted of phosphatidylethanolamine, aminolipid and an unidentified lipid. Strain ARC111T harboured sym-homospermidine as the major polyamine. Characteristic differences obtained using polyphasic analysis of strain ARC111T and its closest relatives suggested that strain ARC111T is a novel species of genus Subsaxibacter, for which the name Subsaxibacter sediminis sp. nov. has been proposed. The type strain is ARC111T (=MCC 3191T=KCTC 42965T=LMG 29783T=GDMCC 1.1201T).

Arenibacter catalasegens sp. nov., isolated from marine surface sediment, and emended description of the genus Arenibacter.

A Gram-staining-negative, aerobic, non-motile, rod-shaped bacterium, designated as P308H10T, was isolated from surface sediment of the Southern Indian Ocean. Growth occurred at 4-36 °C (optimum 20-25 °C), pH 6.0-8.5 (optimum 7.5-8.0) and in the presence of 1-8 % (w/v) NaCl (optimum 2-3 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain P308H10T lies within the clade of members of the genus Arenibacter and is closely related to Arenibacterhampyeongensis HP12T (98.0 %), Arenibacterechinorum KMM 6032T (98.4 %), Arenibacterpalladensis LMG 21972T (97.9 %), Arenibactertroitsensis KMM 3674T (97.9 %) and 'Arenibacter algicola' TG409 (98.1 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain P308H10T and the five reference strains were 85.9-80.6 % and 30.2-23.6 %, respectively. The major fatty acids (>10 %) of strain P308H10T were summed feature 3, iso-C17 : 0 3-OH, iso-C15 : 1 G and iso-C15 : 0. The major polar lipids comprised phosphatidylethanolamine, five unidentified aminolipids and four unidentified lipids. The only respiratory quinone was menaquinone-6. The genomic DNA G+C content was 38.2 mol%. On the basis of the phenotypic, phylogenetic and chemotaxonomic data presented, strain P308H10T represents a novel species of the genus Arenibacter, for which the name Arenibacter catalasegens sp. nov. is proposed. The type strain is P308H10T (=GDMCC 1.1230T=KCTC 52983T). An emended description of the genus Arenibacter is also proposed.

Emended descriptions of the species Sphingomonas adhaesiva Yabuuchi et al. 1990 and Sphingomonas ginsenosidimutans Choi et al. 2011.

During the phylogenetic study of the genus Sphingomonas and its closely related genera, we found that there existed errors in the 16S rRNA gene sequence of the type strain of the type species of Sphingomonas adhaesiva (D13722). Data suggested the wrong sequence should be replaced by the sequence under the accession number KY927401. As the new sequence shared 99.6 % 16S rRNA gene sequence similarity with that of Sphingomonas ginsenosidimutans, the relationship between these two species was reevaluated in the present study. Analyses, based on the whole genome sequences, phenotypic characteristics and fatty acid profiles clearly show that S. adhaesiva and Sphingomonas ginsenosidimutans are two distinct species of the genus Sphingomonas. Considering the errors in the original descriptions of S. adhaesiva and S. ginsenosidimutans, we have emended the descriptions of the two species.

Antarcticibacterium flavum gen. nov., sp. nov., isolated from marine sediment.

A Gram-stain-negative, strictly aerobic, yellow-pigmented, non-gliding, oval to rod-shaped bacterial strain, designated JB01H24T, belonging to the family Flavobacteriaceae, was isolated from marine surface sediment collected from the Ross Sea, Antarctica. Strain JB01H24T grew at 4-40 °C (optimum 25-30 °C), pH 7.0-9.0 (optimum 7.5-8.0), and in the presence of 0-8 % NaCl (optimum 3 %, w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JB01H24T formed an independent linkage within the family Flavobacteriaceae and was closely related with the genus Gillisia. Strain JB01H24T exhibited 16S rRNA gene sequence similarities of 95.3-91.5 % and 94.9-94.0 % to the type strains of the genera Gillisia and Salinimicrobium, respectively. The major fatty acids (>5 %) were iso-C15 : 0, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), anteiso-C15 : 0, iso-C15 : 1 G and summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0). The major polar lipids were phosphatidylethanolamine, seven unidentified lipids, two unidentified aminolipids and an unidentified aminophospholipid. Strain JB01H24T contained menaquinone-6 as the only ubiquinone. The DNA G+C content was 42.4 mol%. On the basis of phylogenetic, physiological and chemotaxonomic properties, strain JB01H24T is considered to represent a novel species of a new genus within the family Flavobacteriaceae, for which the name Antarcticibacterium flavum gen. nov., sp. nov. is proposed. The type strain of Antarcticibacterium flavum is JB01H24T (=GDMCC 1.1229T=KCTC 52984T).