Sphingomicrobium clamense sp. nov., Isolated from Sediment of Clam Island Beach in China

A Gram-stain-negative, non-flagellated, aerobic, ovoid or rod-shaped bacterium with motility, designated B8T, was isolated from the sediment of Clam Island beach, Liaoning province, China. The optimum growth of strain B8T occurred at 35 oC, pH 7.0, and in the presence of 4.0-5.0% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain B8T formed a distinct lineage within the genus Sphingomicrobium and was closely related to Sphingomicrobium nitratireducens O-35T (98.3% sequence similarity), Sphingomicrobium aestuariivivum KCTC 42286T (96.9%), and Sphingomicrobium astaxanthinifaciens JCM 18551T (96.5%). The digital DNA-DNA hybridization and average nucleotide identity values between strain B8T and closely related strains were lower than 21.0% and 78.0%, much lower than the cutoff values of 70.0% and 95.0%, respectively, for bacterial species delineation. The dominant respiratory quinone of strain B8T was ubiquinone-10. The major fatty acids were Sum In Feature 8 (C18:1ω7c and/or C18:1ω6c), Sum In Feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C17:1ω6c, C18:1 2-OH, and C16:0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, glycolipids, and four unknown polar lipids. The DNA G + C content of strain B8T was 63.9%. Based on the phenotypic, phylogenetic, and chemotaxonomic analyses, strain B8T is considered a new species of Sphingomicrobium, for which the name Sphingomicrobium clamense sp. nov. is proposed. The type strain is B8T (= CGMCC 1.19486T = KCTC 92052T).

Sphingomicrobium nitratireducens sp. nov., isolated from a tidal flat in Guangxi

An aerobic, yellow-pigmented and Gram-stain-negative strain, designated as O-35 ^T, was isolated from a tidal flat sediment collected in Dangjiang Town, the southern China. Colonies of strain O-35 ^T were circular with 0.5-1.0 mm in diameter, convex and smooth. Cells of strain O-35 ^T were coccoid-shaped, non-spore forming, non-motile and the strain could reduce nitrate. Growth of strain O-35 ^T was observed at 15-40 °C (optimum 30 °C), at pH 6.0-9.5 (optimum 7.5-8.0) and in 0.5-5.0% NaCl (optimum 2%, w/v). Strain O-35 ^T showed 16S rRNA gene sequence identities of 97.3-97.5% with Sphingomicrobium lutaoense CC-TBT-3 ^T and Sphingomicrobium aestuariivivum AH-M8^T, higher than the rest of Sphingomicrobium type strains. Phylogenetic trees based on the 16S rRNA gene and the core-genome sequences demonstrated that strain O-35 ^T was affiliated within the genus Sphingomicrobium. Overall genome relatedness index calculations revealed that strain O-35 ^T had < 75.8% of average nucleotide identity and < 19.2% of digital DNA-DNA hybridization values with Sphingomicrobium type strains. The sole isoprenoid quinone was ubiquinone-10. The major fatty acids (> 10%) were summed feature 8, summed feature 3, C_16:0 and C_18:1 2-OH. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, sphingoglycolipid, two unidentified glycolipids, one unidentified lipid and one unidentified phospholipid. On the basis of the phenotypic, chemotaxonomic and genomic properties, strain O-35 ^T represents a novel species in the genus Sphingomicrobium, for which the name Sphingomicrobium nitratireducens sp. nov. is proposed. The type strain is O-35 ^T (= KCTC 92308 ^T = MCCC 1K07589^T).

Analysis of the Microbiome (Bathing Biome) in Geothermal Waters from an Australian Balneotherapy Centre

Balneotherapy is an ancient practice which remains commonplace throughout the world due to perceived health benefits that include relief of arthritis, fibromyalgia and relaxation. However, bathing environments are not sterile and natural spring waters may harbour natural microbial populations that include potential pathogens. We elucidated the microbial community from water taken from the borehole, pre-filter water (chlorinated, cold and post-bathing water) and post-filter water at a commercial Australian natural hot spring bathing facility. Thiobacillus, Sphingobium and Agrobacterium were the predominant genera in samples collected from the borehole. The predominant genera changed to Sphingobium, Parvibaculum and Achromobacter following chloride treatment and Azospira replaced the Achromobacter once the water reached ambient temperature and was stored ready to be used by bathers. The microbial community changed again following use by bathers, dominated by Pseudomonas, although Sphingobium persisted. No total or faecal coliforms were observed in any of the samples except for the post-bathing water; even there, their presence was at very low concentration (2.3 cfu/mL). These results confirm the lack of pathogens present in these hot spring waters but also suggests that good management of post-bathing water is required especially if the water is used for borehole water recharge.

Transfer of Sphingorhabdus marina, Sphingorhabdus litoris, Sphingorhabdus flavimaris and Sphingorhabdus pacifica corrig. into the novel genus Parasphingorhabdus gen. nov. and Sphingopyxis baekryungensis into the novel genus Novosphingopyxis gen. nov. within the family Sphingomonadaceae

During a phylogenetic analysis of Sphingorhabdus and its closely related genera in the family Sphingomonadaceae, we found that the genus Sphingorhabdus and the species Sphingopyxis baekryungensis might not be properly assigned in the taxonomy. Phylogenetic, phenotypic and chemotaxonomic characterizations clearly showed that the genus Sphingorhabdus should be reclassified into two genera (Clade I and Clade II), for which the original genus name, Sphingorhabdus, is proposed to be retained only for Clade I, and a new genus named as Parasphingorhabdus gen. nov. is proposed for Clade II with four new combinations: Parasphingorhabdus marina comb. nov., Parasphingorhabdus litoris comb. nov., Parasphingorhabdus flavimaris comb. nov. and Parasphingorhabdus pacifica comb. nov. Moreover, Sphingopyxis baekryungensis should represent a novel genus in the family Sphingomonadaceae, for which the name Novosphingopyxis gen. nov. is proposed, with a combination of Novosphingopyxis baekryungensis comb. nov. The study provides a new insight into the taxonomy of closely related genera in the family Sphingomonadaceae.

Description of novel members of the family Sphingomonadaceae: Aquisediminimonas profunda gen. nov., sp. nov., and Aquisediminimonas sediminicola sp. nov., isolated from freshwater sediment

Two Gram-stain-negative bacterial strains, DS48-3^T and CH68-4^T, were isolated from freshwater sediment taken from the Daechung Reservoir, Republic of Korea. Cells of strains DS48-3^T and CH68-4^T were aerobic, non-motile, non-spore-forming and rod-shaped. Strain DS48-3^T was isolated from a sediment surface sample at a depth of 48 m from the Daechung Reservoir and was most closely related to the genus Sphingopyxis according to 16S rRNA gene sequence analysis (94.5-95.9 % similarity). Strain CH68-4^T was isolated from the very bottom of a 67-cm-long sediment core collected from Daechung Reservoir at a water depth of 17 m and was most closely related to the genus Sphingopyxis (16S rRNA gene sequence similarity of 93.7-95.0 %). Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the two strains formed a separate lineage within the order Sphingomonadales showing similarity values below 95.9 % with their closest phylogenetic neighbours, and sharing 97.3 % similarity with each other. The combined genotypic and phenotypic data showed that strains DS48-3^T and CH68-4^T could be distinguished from all genera within the family Sphingomonadaceae and represented two distinct species of a novel genus, Aquisediminimonas profunda gen. nov., sp. nov. (type strain DS48-3^T=KCTC 52068^T=CCTCC AB 2018061^T) and Aquisediminimonas sediminicola sp. nov. (type strain CH68-4^T=KCTC 62205^T=CCTCC AB 2018062^T).

Sphingomicrobium arenosum sp. nov., isolated from marine sediment

A Gram-stain-negative, strictly aerobic, motile by one single flagellum, dark-orange pigmented and rod-shaped bacterial strain, designated CAU 1457^T, was isolated from marine sediment in the Republic of Korea and its taxonomic position was investigated by using a polyphasic approach. The isolate grew optimally at 30 °C, at pH 6.0 and in the presence of 2 % (w/v) NaCl. Based on 16S rRNA gene sequences similarity, strain CAU 1457^T belonged to the genus Sphingomicrobium and was related most closely to Sphingomicrobium astaxanthinifaciens JCM 18551^T (98.2 % similarity). Strain CAU 1457^T contained ubiquinone-10 as the predominant isoprenoid quinone and 11-methyl C18 : 1ω7c and summed feature 8 (C18 : 1ω7c/ω6c) as the major cellular fatty acids. Triamine sym-homospermidine was detected as the major compound in the polyamine pattern. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, four unidentified glycolipids, one unidentified aminophospholipid, two unidentified phospholipids, one unidentified aminolipid and one unidentified lipid. DNA-DNA relatedness between strain CAU 1457^T and the closely related strains, Sphingomicrobium astaxanthinifaciens JCM 18551^T and Sphingomicrobium aestuariivivum KCTC 42286^T were 32.7 and 28.4 %, respectively. The DNA G+C content of strain was 68.8 mol%. The phenotypic, chemotaxonomic and phylogenetic data indicated that strain CAU 1457^T represents a novel species of the genus Sphingomicrobium, for which the name Sphingomicrobium arenosum sp. nov. is proposed. The type strain is CAU 1457^T (=KCTC 62233^T=NBRC 113094^T).

Tardibacter chloracetimidivorans gen. nov., sp. nov., a novel member of the family Sphingomonadaceae isolated from an agricultural soil from Jeju Island in Republic of Korea

A pale yellow bacterial strain, designated JJ-A5^T, was isolated form an agricultural soil from Jeju Island in Republic of Korea. Cells of the strain were Gram-stain-negative, motile, flagellated and rod-shaped. The strain grew at 15-30°C, pH 6.0-9.0, and in the presence of 0-1.5% (w/v) NaCl. Growth occurred on R2A, but not on Luria-Bertani agar, nutrient agar, trypticase soy agar and MacConkey agar. The strain utilized alachlor as a sole carbon source for growth. The strain JJ-A5^T showed 16S rRNA gene sequence similarities lower than 95.4% with members of the family Sphingomonadaceae. Phylogenetic analysis showed that the strain belongs to the family Sphingomonadaceae and strain JJ-A5^T was distinctly separated from established genera of this family. The strain contained Q-10 as dominant ubiquinone and spermidine as major polyamine. The predominant cellular fatty acids were summed feature 8 (C_18:1ω7c and/or C_18:1ω6c), summed feature 3 (C_16:1ω7c and/or C_16:1ω6c), 11-methyl C_18:1ω7c, C_16:0 and C_14:0 2-OH. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, and phosphatidylcholine. The DNA G + C content of the strain was 62.7 mol%. On the basis of the phenotypic, genomic and chemotaxonomic characteristics, strain JJ-A5^T is considered to represent a novel genus and species within the family Sphingomonadaceae, for which the name Tardibacter chloracetimidivorans gen. nov., sp. nov. is proposed. The type strain of Tardibacter chloracetimidivorans is JJ-A5^T (= KACC 19450^T = NBRC 113160^T).

Binariimonas pacifica gen. nov., sp. nov., a Novel Marine Bacterium of Family Sphingomonadaceae Isolated from East Pacific Ocean Surface Seawater

A novel rod-shaped binary fission, and yellow-pigmented bacterial strain, JLT 2480(T), was isolated from surface seawater in the East Pacific Ocean. The strain is Gram negative and oxidase negative. Phylogenetic analyses based on 16S rRNA gene sequence indicate that strain JLT 2480(T) falls in the family Sphingomonadaceae, sharing highest similarity (95.6 %) with the species Blastomonas ursincola. The DNA G+C content of JLT 2480(T) is 65.5 mol%, and the sole respiratory quinone is coenzyme Q10. The predominant polar lipids are sphingoglycolipids (SGL1 and SGL2), phosphatidylglycerols, phosphatidylethanolamines, phospholipids, glycolipids, and phosphatidylcholines. The predominant cellular fatty acids are C16:0, C18:0, C18:1ω7c, C12:0, and C16:1ω7c. Strain JLT 2480(T) is distinct from the B. ursincola type strain DSM 9006(T) as reflected by major chemotaxonomic distinctions between the two. Furthermore, two notable characteristics of the genus Blastomonas, that is, the presence of bacteriochlorophyll a and the puf genes, are not detected in JLT 2480(T). On the basis of present evidence, we consider JLT 2480(T) to be a novel species in a new genus of the family Sphingomonadaceae, and propose the name Binariimonas pacifica gen. nov., sp. nov., with strain JLT 2480(T) (=CGMCC 1.12850(T) = DSM 28646(T)) to be the type strain for genus Binariimonas.

Sphingomonas chloroacetimidivorans sp. nov., a chloroacetamide herbicide-degrading bacterium isolated from activated sludge

Strain Y1(T), a Gram-negative, non-spore-forming, rod-shaped bacterium, was isolated from activated sludge. This strain is able to degrade several commonly used chloroacetamide herbicides, such as butachlor, acetochlor and alachlor. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Y1(T) is a member of the genus Sphingomonas and shows high sequence similarities with S. starnbergensis 382(T) (95.7 %), S. sanxanigenens NX02(T) (95.7 %) and S. haloaromaticamans A175(T) (95.3 %), and shows low (<95 %) sequence similarities to all other Sphingomonas species. Chemotaxonomic analysis revealed that strain Y1(T) possesses Q-10 as the predominant ubiquinone, C14:0 2-OH as the major 2-hydroxy fatty acid and sym-homospermidine as the major polyamine. The main cellular fatty acids of strain Y1(T) were found to be C18:1 ω7c (38.2 %), C16:1 ω6c/C16:1 ω7c (28.5 %), C16: 0 (10.7 %) and C14:0 2-OH (14.3 %). The main polar lipids were determined to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipids (SGL1-SGL3), phosphatidyl dimethylethanolamine and aminophospholipid. The DNA G+C content was found to be 66 ± 0.4 mol%. Based on phylogenetic analysis, phenotypic characteristics and chemotaxonomic data, strain Y1(T) is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas chloroacetimidivorans sp. nov. is proposed. The type strain is Y1(T) (=CCTCC AB 2011178(T) = KACC 16607(T)).

Sphingomicrobium aestuariivivum sp. nov., isolated from a tidal flat

A Gram-stain-negative, aerobic, non-spore-forming, non-flagellated and coccoid, ovoid or rod-shaped bacterial strain, designated AH-M8T, was isolated from a tidal flat sediment collected from Aphae Island in the south-western sea, South Korea. Strain AH-M8T grew optimally at 35 °C, at pH 7.0-8.0 and in the presence of 2.0-3.0% (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain AH-M8T belonged to the genus Sphingomicrobium, clustering with the type strain of Sphingomicrobium astaxanthinifaciens, with which it shared 99.0% 16S rRNA gene sequence similarity. Sequence similarities to the type strains of other species of the genus Sphingomicrobium were 95.4-96.0%. Strain AH-M8T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0 as the major fatty acids. The major polar lipids of strain AH-M8T were phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid and one unidentified glycolipid. The major polyamine is triamine sym-homospermidine. The DNA G+C content of strain AH-M8T was 66.7 mol% and its mean DNA-DNA relatedness value with S. astaxanthinifaciens JCM 18551T was 21%. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain AH-M8T is separated from other species of the genus Sphingomicrobium. On the basis of the data presented, strain AH-M8T is considered to represent a novel species of the genus Sphingomicrobium, for which the name Sphingomicrobium aestuariivivum sp. nov. is proposed. The type strain is AH-M8T ( = KCTC 42286T = NBRC 110678T).

Parablastomonas arctica gen. nov., sp. nov., isolated from high Arctic glacial till

A pale yellow, aerobic bacterium, strain M0-2T, was isolated from a till sample. Its taxonomic position was investigated by using a polyphasic approach. Cells were Gram-stain-negative, rod-shaped and motile. Cells reproduced by budding or asymmetrical cell division. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain M0-2T belonged to the family Sphingomonadaceae and was closely related to species of the genera Novosphingobium (96.4–92.0 %) and Blastomonas (94.6 %), Sphingopyxis witflariensis W-50T (94.0 %), Sphingosinicella soli KSL-125T (93.6 %) and Sphingomonas astaxanthinifaciens TDMA-17T (93.5 %). Ubiquinone-10 (Q-10) was the predominant respiratory quinone. The major fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c, 31.9 %), summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c, 19.8 %) and C14 : 0 2-OH (8.9 %). Sphingoglycolipid, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylcholine were the major polar lipids. Spermidine was the major polyamine observed in the cell. The genomic DNA G+C content was 47.5 mol%. On the basis of phylogenetic relationships and the low DNA G+C content compared with most other genera of the family Sphingomonadaceae , combined with phenotypic and chemotaxonomic data, strain M0-2T is considered to represent a novel species in a new genus in the family Sphingomonadaceae for which the name Parablastomonas arctica gen. nov., sp. nov. is proposed. The type strain of Parablastomonas arctica gen. nov., sp. nov. is M0-2T ( = CCTCC AB 2012968T = NRRL B-59110T).

Polymorphobacter multimanifer gen. nov., sp. nov., a polymorphic bacterium isolated from Antarctic white rock

A Gram-stain-negative, non-spore-forming, aerobic, oligotrophic bacterium (strain 262-7(T)) was isolated from a crack of white rock collected in the Skallen region of Antarctica. Strain 262-7(T) grew at temperatures between -4 and 30 °C, with optimal growth at 25 °C. The pH range for growth was between pH 6.0 and 9.0, with optimal growth at approximately pH 7.0. The NaCl concentration range allowing growth was between 0.0 and 1.0%, with an optimum of 0.5%. Strain 262-7(T) showed an unprecedented range of morphological diversity in response to growth conditions. Cells grown in liquid medium were circular or ovoid with smooth surfaces in the lag phase. In the exponential phase, ovoid cells with short projections were observed. Cells in the stationary phase possessed long tentacle-like projections intertwined intricately. By contrast, cells grown on agar plate medium or in liquid media containing organic compounds at low concentration exhibited short- and long-rod-shaped morphology. These projections and morphological variations clearly differ from those of previously described bacteria. Ubiquinone 10 was the major respiratory quinone. The major fatty acids were C(17 : 1)ω6c (28.2%), C(16 : 1)ω7c (22.6%), C(18 : 1)ω7c (12.9%) and C(15 : 0) 2-OH (12.3%). The G+C content of genomic DNA was 68.0 mol%. Carotenoids were detected from the cells. Comparative analyses of 16S rRNA gene sequences indicated that strain 262-7(T) belongs to the family Sphingomonadaceae, and that 262-7(T) should be distinguished from known genera in the family Sphingomonadaceae. According to the phylogenetic position, physiological characteristics and unique morphology variations, strain 262-7(T) should be classified as a representative of a novel genus of the family Sphingomonadaceae. Here, a novel genus and species with the name Polymorphobacter multimanifer gen. nov., sp. nov. is proposed (type strain 262-7(T) = JCM 18140(T) = ATCC BAA-2413(T)). The novel species was named after its morphological diversity and formation of unique projections.

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

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

Sphingomicrobium astaxanthinifaciens sp. nov., an astaxanthin-producing glycolipid-rich bacterium isolated from surface seawater and emended description of the genus Sphingomicrobium

A Gram-stain-negative, rod-shaped, strictly aerobic, flagellated and non-spore-forming marine bacterium designated strain CC-AMO-30BT was isolated from coastal surface seawater, Taiwan. Strain CC-AMO-30BT synthesized astaxanthin [40 µg (g dry weight)−1] and formed reddish-orange-coloured colonies on marine agar (Difco 2216). The strain showed highest pairwise 16S rRNA gene sequence similarity to Sphingomicrobium lutaoense CC-TBT-3T (96.4 %) followed by other members of the family Sphingomonadaceae (<94 %) and established a discrete phyletic lineage associated with the former. The polar lipid profile constituted a remarkable number of unidentified glycolipids (GL1–8), in addition to diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid and two unidentified lipids (L1–2). The major fatty acids (>5 % of total fatty acids) were C18 : 1ω7c/C18 : 1ω6c (summed feature 8), C16 : 1ω7c/C16 : 1ω6c (summed feature 3), C18 : 1 2-OH, methyl C18 : 1ω7c, C17 : 1ω6c and C16 : 0. DNA G+C content was 70.6 %; major respiratory quinone was ubiquinone Q-10; predominant polyamine was the triamine sym-homospermidine. Chemotaxonomic evidence including characteristic glycolipid profile, presence of significant amounts of C18 : 1 2-OH and absence of typical hydroxylated fatty acids such as C14 : 0 2-OH, C15 : 0 2-OH and C16 : 0 2-OH in considerable amounts, accompanied by phylogenetic distinctiveness and several other phenotypic features support the classification of strain CC-AMO-30BT as a representative of a novel species within the genus Sphingomicrobium for which the name Sphingomicrobium astaxanthinifaciens sp. nov. is proposed; the type strain is CC-AMO-30BT ( = JCM 18551T = BCRC 80465T).

Sphingomicrobium marinum sp. nov. and Sphingomicrobium flavum sp. nov., isolated from surface seawater, and emended description of the genus Sphingomicrobium

Two Gram-staining-negative, yellow-pigmented, rod-shaped, strictly aerobic, non-flagellated and non-spore-forming amylolytic marine bacterial strains, designated CC-AMZ-30M(T) and CC-AMZ-30N(T), were isolated from coastal surface seawater in Taiwan. Strain CC-AMZ-30M(T) shared pairwise 16S rRNA gene sequence similarities of 95.8, 95.0 and <94.0 % to Sphingomicrobium lutaoense CC-TBT-3(T), Sphingomicrobium astaxanthinifaciens CC-AMO-30B(T) and other sphingomonads, respectively. Strain CC-AMZ-30N(T) shared 97.0, 96.7, 95.0 and <95.1 % similarities to strain CC-AMZ-30M(T), Sphingomicrobium lutaoense CC-TBT-3(T), Sphingomicrobium astaxanthinifaciens CC-AMO-30B(T) and other sphingomonads, respectively. The common polar lipids of the two strains include a signature glycolipid (GL2), diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and sphingoglycolipid in major amounts besides moderate-to-trace amounts of an unidentified aminolipid and several unidentified glycolipids. Both strains contained C18 : 1ω7c/C18 : 1ω6c, C16 : 1ω7c/C16 : 1ω6c, C16 : 0 and C18 : 1 2-OH as major (>5 % of the total) fatty acids. Strains CC-AMZ-30M(T) and CC-AMZ-30N(T) had DNA G+C contents of 64.2 and 65.2 mol%, respectively. The major polyamine was spermidine in strain CC-AMZ-30M(T) and triamine sym-homospermidine in strain CC-AMZ-30N(T). Both strains contained ubiquinone Q-10 as the predominant respiratory quinone. Differential phylogenetic and chemotaxonomic evidence including the presence of characteristic GL2, C18 : 1 2-OH and several other phenotypic features supported the classification of strains CC-AMZ-30M(T) and CC-AMZ-30N(T) as two novel species of the genus Sphingomicrobium, for which we propose the names Sphingomicrobium marinum sp. nov. and Sphingomicrobium flavum sp. nov., respectively; corresponding type strains are Sphingomicrobium marinum CC-AMZ-30M(T) ( = JCM 18554(T) = BCRC 80466(T)) and Sphingomicrobium flavum CC-AMZ-30N(T) ( = JCM 18555(T) = BCRC 80467(T)). An emended description of the genus Sphingomicrobium is also proposed.

Sphingomonas starnbergensis sp. nov., isolated from a prealpine freshwater lake

A novel type of freshwater bacterium was isolated from the prealpine mesotrophic Starnberger See (Bavaria, southern Germany). Cells of strain 382T were Gram-negative and rod-shaped, motile and creamy-white. The isolate was strictly aerobic, catalase- and oxidase-positive, and grew at pH values of 6–9 (optimum, pH 7) and temperatures of 10–37 °C (optimum, 28 °C). The genomic G+C content of strain 382T was 64.1 mol%. Based on 16S rRNA gene sequence analyses, strain 382T belongs to the family Sphingomonadaceae and clusters within the genus Sphingomonas . Sphingomonas histidinilytica UM 2T and Sphingomonas wittichii DSM 6014T were the closest relatives, as indicated by the highest 16S rRNA gene sequence similarities (97.1 % and 96.8 %, respectively). Sphingomonas paucimobilis DSM 1098T (the type species of the genus Sphingomonas ) exhibited 95.3 % sequence similarity. This affiliation of strain 382T to the genus Sphingomonas is confirmed by the presence of Q-10 as the major respiratory quinone, two sphingoglycolipids, C14 : 0 2-OH as the major 2-hydroxy fatty acid and sym-homospermidine as the major polyamine. The main cellular fatty acids of strain 382T were C18 : 1ω7c (39 %), C16 : 1ω7c (21 %), C16 : 0 (10 %) and C14 : 0 2-OH (10 %). Based on the phylogenetic distance from other species of the genus Sphingomonas and its unusually high C16 : 1ω7c content, strain 382T represents a novel species of the genus Sphingomonas , for which the name Sphingomonas starnbergensis is proposed. The type strain is 382T ( = DSM 25077T  = LMG 26763T).

Sphingobium limneticum sp. nov. and Sphingobium boeckii sp. nov., two freshwater planktonic members of the family Sphingomonadaceae , and reclassification of Sphingomonas suberifaciens as Sphingobium suberifaciens comb. nov

Two novel chemo-organoheterotrophic members of the Sphingomonadaceae were isolated from alpine and pre-alpine lakes. Cells stained Gram-negative, were motile and rod-shaped, and formed yellow, circular, convex colonies on different agar media. Strains 301T and 469T were strictly aerobic, catalase- and oxidase-positive, and grew at temperatures between 10 and 40 °C (optimum, 28 °C), and at pH values between 5 and 10 (optimum, pH 7). Both strains contained Q-10 as the dominant quinone, sphingoglycolipids and 2-hydroxymyristic acid, whereas 3-hydroxy fatty acids were absent. Major fatty acids of strain 301T were C18 : 1ω7c (53.3 %) and C16 : 1ω7c (22.9 %), with C14 : 0 2-OH (10.8 %) as the major 2-hydroxy fatty acid. Fatty acids of strain 469T were dominated by C18 : 1ω7c (34.4 %), C16 : 1ω7c (32.0 %) and C14 : 0 2-OH (15.2 %) as the major 2-hydroxy fatty acid. The genomic DNA G+C contents of strains 301T and 469T were 63.4 and 64.6 mol%, respectively. 16S rRNA gene sequence comparison indicated that both strains belonged to the genus Sphingobium . This classification was supported by the presence of spermidine as the major polyamine. The phylogenetically closest relatives of strain 301T were Sphingobium amiense DSM 16289T, Sphingobium vermicomposti DSM 21299T, Sphingobium yanoikuyae DSM 7462T and Sphingobium scionense DSM 19371T (98.8, 98.0, 97.9 and 97.4 % sequence similarity, respectively). DNA–DNA hybridization of genomic DNA yielded similarities in the range 43.2–12.1 % between strain 301T and the type strains of these four Sphingobium species. Closest relatives of strain 469T were Sphingomonas suberifaciens DSM 7465T and Sphingobium scionense DSM 19371T (97.1 and 96.5 % 16S rRNA gene sequence similarity, respectively). The degree of DNA–DNA hybridization between strain 469T and Sphingomonas suberifaciens DSM 7465T was 17.9 %. Based on the results of the molecular analyses and their phenotypic characteristics, strains 301T and 469T represent two novel species of the genus Sphingobium . The name Sphingobium limneticum sp. nov. is proposed for strain 301T( = DSM25076T = LMG 26659T). The name Sphingobium boeckii sp. nov. is proposed for strain 469T ( = DSM 25079T = LMG 26901T). The polyphasic analysis also suggests that Sphingomonas suberifaciens should be reclassified as Sphingobium suberifaciens comb. nov. with Ca1T ( = EY 2404T = ATCC 49355T = CIP 105429T = DSM 7465T = ICMP 12535T = NBRC 15211T = JCM 8521T = LMG 17323T = NCPPB 3629T) as the type strain.

Description of Sphingorhabdus planktonica gen. nov., sp. nov. and reclassification of three related members of the genus Sphingopyxis in the genus Sphingorhabdus gen. nov

A previously undescribed aerobic, non-sporulating bacterium, strain G1A_585(T), was isolated from an oligotrophic freshwater lake in Bavaria, Germany. The rod-shaped cells were Gram-stain-negative and non-motile. Based on 16S rRNA gene sequence similarity, strain G1A_585(T) was a member of the family Sphingomonadaceae and shared <95.2 % similarity with type strains of all members of the most closely related genus, Sphingopyxis. Phyogenetically, the isolate shared a root with strains of three marine species, Sphingopyxis flavimaris DSM 16223(T), Sphingopyxis marina DSM 22363(T) and Sphingopyxis litoris DSM 22379(T). The polar lipids of strain G1A_585(T) were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine, sphingoglycolipids, three glycolipids and one unknown lipid. Ubiquinone-10 was the dominant quinone (93.1 %) and ubiquinone-9 (6.5 %) was also detected. The major cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 38.2 %); C16 : 1ω7c (33.6 %) and C14 : 0 2-OH (17.8 %). The major polyamine was spermidine and traces of 1,3-diaminopropane, putrescine and spermine were also detected. The DNA G+C content of strain G1A_585(T) was 55.7 mol% and the isolate was oxidase- and catalase-positive. Based on the phylogenetic relationship, the low DNA G+C content compared with most other members of the genus Sphingopyxis and the presence of signature nucleotides in the 16S rRNA gene sequence, a novel species in a new genus and species, Sphingorhabdus planktonica gen. nov., sp. nov., is proposed; the type strain of Sphingorhabdus planktonica is G1A_585(T) ( = DSM 25081(T)  = LMG 26646(T)). Because Sphingopyxis flavimaris DSM 16223(T), Sphingopyxis marina DSM 22363(T) and Sphingopyxis litoris DSM 22379(T) form a phylogenetic group together with strain G1A_585(T) that is clearly separated from all other known Sphingopyxis strains and share signature nucleotides, these three Sphingopyxis strains are reclassified as members of the proposed novel genus Sphingorhabdus: Sphingorhabdus flavimaris comb. nov. (type strain SW-151(T) = DSM 16223(T) = KCTC 12232(T)), Sphingorhabdus marina comb. nov. (type strain FR1087(T) = DSM 22363(T) = IMSNU 14132(T) = KCTC 12763(T) = JCM 14161(T)) and Sphingorhabdus litoris comb. nov. (type strain FR1093(T) = DSM 22379(T) = IMSNU 14133(T) = KCTC 12764(T) = JCM 14162(T)).