Erythrobacter flavus sp. nov., a slight halophile from the East Sea in Korea

Description of Qipengyuania profunda sp. nov., isolated from deep seawater of the Amundsen Sea (Antarctica), and reclassification of Qipengyuania aerophila Liu et al. 2022 as a later heterotypic synonym of Qipengyuania pacifica Tareen et al. 2022

Gram-stain-negative, aerobic, rod-shaped bacterial strains, designated HL-TH1T and HL-TH5, were isolated from deep seawater (1127 m depth) of the Amundsen Sea, Antarctica. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that strains HL-TH1T and HL-TH5 were members of the genus Qipengyuania with close relatives Qipengyuania aerophila GH25T (99.3%), Qipengyuania pacifica NZ-96T (99.3%), Qipengyuania profundimaris G39T (99.1%) and Qipengyuania citrea RE35F/1T (98.8%). The complete genome sequences of strains HL-TH1T and HL-TH5 comprised a chromosome of 3.2 Mbp and a plasmid of 0.1 Mbp, with DNA G+C content of 64.1%. The whole genome-based comparisons using the average nt identity and digital DNA-DNA hybridization values revealed that both strains belonged to the same genomic species but were clearly discriminated (79.4-85.8% and 21.9-29.3%, respectively) from their close relatives in the genus Qipengyuania. Both strains showed optimal growth at 30 °C, pH 6.5-7.0 and 1.5-2.5% sea salts. The major fatty acids of both strains were C18:1  ω6c and/or C18:1  ω7c (37.8-38.4%), C17:1  ω6c (18.1-19.7%) and C16:1  ω6c and/or C16:1  ω7c (12.3-16.7%). The major isoprenoid quinone was ubiquinone-10. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and two unidentified lipids. Hence, we propose that strains HL-TH1T and HL-TH5 are assigned to a novel species belonging to the genus Qipengyuania, for which the name Qipengyuania profunda sp. nov. is proposed. The type strain is HL-TH1T (=KCCM 90517T=JCM 36585T). In addition, Q. aerophila GH25T and Q. pacifica NZ-96T were found to be the same species based on a polyphasic approach. Therefore, we propose the reclassification of Q. aerophila as a later heterotypic synonym of Q. pacifica.

Passivation of metal sulfides by a marine bacterium for acid mine drainage control

Acid mine drainage originates from metal sulfides oxidation, which results in acidic metal-rich leachate. In this study, a novel and environmentally friendly approach was demonstrated to passivate pyrite and lead-zinc tailings, respectively. The key to this approach is to develop biofilms of the marine bacterium Qipengyuania flava S1. Biofilms can induce biomineralization, thereby isolating metal sulfides from air and water. The stability and biological toxicity of the bio-passivation layers were evaluated by leaching bio-passivated pyrite or tailings in initially acidic H2O2 solutions with shaking for 180 days and then cultivating Brassica chinensis and Allium cepa with the leachates. Our results showed that after passivation, the amount of iron released by pyrite decreased by at least 99.2 ± 0.2 (in wt%). For lead-zinc tailings after passivation, the released metal ions (Fe+Al+Pb+Zn) decreased by at least 52.0 ± 3.2 (in wt%). The bio-passivation layers also maintained the pH of the leachate in the range of 7.5-8.0. Before bio-passivation, compared with mineral water, the pyrite leachate significantly inhibited the growth of the two plants, and the tailings leachate significantly inhibited the growth of A. cepa, whereas the bio-passivated pyrite or tailings leachate did not show any inhibitory effect.

Qipengyuania benthica sp. nov. and Qipengyuania profundimaris sp. nov., two novel Erythrobacteraceae members isolated from deep-sea environments

Two Gram-stain-negative, rod-shaped and non-motile strains, designated as DY56-A-20T and G39T, were isolated from deep-sea sediment of the Pacific Ocean and deep-sea seawater of the Indian Ocean, respectively. Strain DY56-A-20T was found to grow at 15-37 °C (optimum, 28 °C), at pH 6.0-10.0 (optimum, pH 6.5-7.0) and in 0.5-6.0 % (w/v) NaCl (optimum, 1.0-2.0 %), while strain G39T was found to grow at 10-42 °C (optimum, 35-40 °C), at pH 5.5-10.0 (optimum, pH 6.5-7.0) and in 0-12.0 % (w/v) NaCl (optimum, 1.0-2.0 %). The 16S rRNA gene sequence identity analysis indicated that strain DY56-A-20T had the highest sequence identity with Qipengyuania marisflavi KEM-5T (97.6 %), while strain G39T displayed the highest sequence identity with Qipengyuania citrea H150T (98.8 %). The phylogenomic reconstruction indicated that both strains formed independent clades within the genus Qipengyuania. The digital DNA-DNA hybridization and average nucleotide identity values between strains DY56-A-20T/G39T and Qipengyuania/Erythrobacter type strains were 17.8-23.8 % and 70.7-81.1 %, respectively, which are below species delineation thresholds. The genome DNA G+C contents were 65.0 and 63.5 mol% for strains DY56-A-20T and G39T, respectively. The predominant cellular fatty acids (>10 %) of strain DY56-A-20T were C17 : 1  ω6c, summed feature 8 and summed feature 3, and the major cellular fatty acids of strain G39T were C17 : 1  ω6c and summed feature 8. The major polar lipids in both strains were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified polar lipid. The only respiratory quinone present in both strains was ubiquinone-10. Based on those genotypic and phenotypic results, the two strains represent two novel species belonging to the genus Qipengyuania, for which the names Qipengyuania benthica sp. nov. and Qipengyuania profundimaris sp. nov. are proposed. The type strain of Q. benthica is DY56-A-20T (=MCCC M27941T=KCTC 92309T), and the type strain of Q. profundimaris is G39T (=MCCC M30353T=KCTC 8208T).

Tianweitania aestuarii sp. nov., isolated from a coastal dune, reclassification of Corticibacterium populi as Tianweitania populi comb. nov., and emended description of the genus Tianweitania

A Gram-stain-negative, aerobic, non-flagellated and coccoid or ovoid bacterial strain, BSSL-BM11T, was isolated from sand of coastal dunes along the Yellow Sea of the Korean peninsula. Strain BSSL-BM11T grew optimally at 30 °C, at pH 7.0-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences, the up-to-date bacterial core gene set and average amino acid identity (AAI) showed that strain BSSL-BM11T forms a cluster with the type strains of Tianweitania sediminis and Corticibacterium populi. Strain BSSL-BM11T showed 16S rRNA gene sequence similarities of 98.3 and 98.0 % to the type strains of T. sediminis and C. populi, respectively, and less than 96.4 % to the type strains of the other recognized species. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain BSSL-BM11T and the type strains of T. sediminis and C. populi were 77.0-84.8 % and 20.0-28.1 %, respectively. The 16S rRNA gene similarity, AAI, ANI and dDDH values between T. sediminis Z8T and C. populi KCTC 42249T were 98.0, 77.4, 76.7 and 20.1 %, respectively. The DNA G+C content of strain BSSL-BM11T from genomic sequence data was 61.3 mol%. Strain BSSL-BM11T contained Q-10 as the predominant ubiquinone and C18 : 1  ω7c, C16 : 0 and cyclo C19 : 0  ω8c as the major fatty acids. The major polar lipids of strain BSSL-BM11T were phosphatidylcholine, phosphatidylglycerol and phosphatidylethanolamine. Based on the polyphasic data, it is proposed that C, populi be reclassified as a member of the genus Tianweitania. Phenotypic and phylogenetic analyses revealed that strain BSSL-BM11T is separated from T. sediminis and C. populi. On the basis of the data presented here, strain BSSL-BM11T (=KACC 21634T=NBRC 114503T) is considered to represent a novel species of the genus Tianweitania, for which the name Tianweitania aestuarii sp. nov. is proposed.

The Diversity and Metabolism of Culturable Nitrate-Reducing Bacteria from the Photic Zone of the Western North Pacific Ocean

To better understand bacterial communities and metabolism under nitrogen deficiency, 154 seawater samples were obtained from 5 to 200 m at 22 stations in the photic zone of the Western North Pacific Ocean. Total 634 nitrate-utilizing bacteria were isolated using selective media and culture-dependent methods, and 295 of them were positive for nitrate reduction. These nitrate-reducing bacteria belonged to 19 genera and 29 species and among them, Qipengyuania flava, Roseibium aggregatum, Erythrobacter aureus, Vibrio campbellii, and Stappia indica were identified from all tested seawater layers of the photic zone and at almost all stations. Twenty-nine nitrate-reducing strains representing different species were selected for further the study of nitrogen, sulfur, and carbon metabolism. All 29 nitrate-reducing isolates contained genes encoding dissimilatory nitrate reduction or assimilatory nitrate reduction. Six nitrate-reducing isolates can oxidize thiosulfate based on genomic analysis and activity testing, indicating that nitrate-reducing thiosulfate-oxidizing bacteria exist in the photic zone. Five nitrate-reducing isolates obtained near the chlorophyll a-maximum layer contained a dimethylsulfoniopropionate synthesis gene and three of them contained both dimethylsulfoniopropionate synthesis and cleavage genes. This suggests that nitrate-reducing isolates may participate in dimethylsulfoniopropionate synthesis and catabolism in photic seawater. The presence of multiple genes for chitin degradation and extracellular peptidases may indicate that almost all nitrate-reducing isolates (28/29) can use chitin and proteinaceous compounds as important sources of carbon and nitrogen. Collectively, these results reveal culturable nitrate-reducing bacterial diversity and have implications for understanding the role of such strains in the ecology and biogeochemical cycles of nitrogen, sulfur, and carbon in the oligotrophic marine photic zone.

Enterovibrio paralichthyis sp. nov., isolated from the gut of an olive flounder Paralichthys olivaceus

A Gram-stain-negative, facultatively anaerobic, flagellated and coccoid, ovoid or rod-shaped bacterial strain, NIFS-20-8^T, was isolated from the intestine of an olive flounder (Paralichthys olivaceus) from the East Sea, Republic of Korea. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain NIFS-20-8^T fell within the clade comprising the type strains of Enterovibrio species. Strain NIFS-20-8^T exhibited 16S rRNA gene sequence similarities of 97.2 and 97.1 % to the type strains of Enterovibrio nigricans and Enterovibrio norvegicus, respectively, and of 96.6-97.0 % to the type strains of the other Enterovibrio species. The average nucleotide identity and digital DNA-DNA hybridization values between the genomic sequence of strain NIFS-20-8^T and those of the type strains of four Enterovibrio species were 73.8-75.0 and 19.8-21.1 %, respectively. The DNA G+C content of strain NIFS-20-8^T from genomic sequence data was 50.55 mol%. Strain NIFS-20-8^T contained Q-8 as the predominant ubiquinone and summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c), C_16 : 0 and C_18 : 1  ω7c as the major fatty acids. The major polar lipids detected in stain NIFS-20-8^T were phosphatidylethanolamine and phosphatidylglycerol. Distinguishing phenotypic properties, together with phylogenetic and genetic distinctiveness, revealed that strain NIFS-20-8^T is separated from recognized Enterovibrio species. On the basis of the data presented here, strain NIFS-20-8^T is considered to represent a novel species of the genus Enterovibrio, for which the name Enterovibrio paralichthyis sp. nov. is proposed. The type strain is NIFS-20-8^T (= KCTC 82873^T=NBRC 115237^T).

Characterization of chlorinated paraffin-degrading bacteria from marine estuarine sediments

This study explored chlorinated paraffin (CP)-degrading bacteria from the marine environment. Aequorivita, Denitromonas, Parvibaculum, Pseudomonas and Ignavibacterium were selected as the dominant genera after enrichment with chlorinated paraffin 52 (CP52) as the sole carbon source. Eight strains were identified as CP degraders, including Pseudomonas sp. NG6 and NF2, Erythrobacter sp. NG3, Castellaniella sp. NF6, Kordiimonas sp. NE3, Zunongwangia sp. NF12, Zunongwangia sp. NH1 and Chryseoglobus sp. NF13, and their degradation efficiencies ranged from 6.4% to 19.0%. In addition to Pseudomonas, the other six genera of bacteria were first reported to have the degradation ability of CPs. Bacterial categories, carbon-chain lengths and chlorination degrees were three crucial factors affecting the degradation efficiencies of CPs, with their influential ability of chlorinated degrees > bacterial categories > carbon-chain lengths. CP degradation can be performed by producing chlorinated alcohols, chlorinated olefins, dechlorinated alcohols and lower chlorinated CPs. This study will provide valuable information on CP biotransformation and targeted bacterial resources for studying the transformation processes of specific CPs in marine environments.

Mesonia aestuariivivens sp. nov., isolated from a tidal flat

A Gram-negative, aerobic, non-flagellated and ovoid or rod-shaped bacterial strain (JHPTF-M18^T), which was isolated from a tidal flat sediment in Republic of Korea, was taxonomically characterized. Strain JHPTF-M18^T grew optimally at 25 °C, at pH 7.0-7.5 and in the presence of 2.0-3.0% (w/v) NaCl. 16S rRNA gene sequence analysis showed that strain JHPTF-M18^T forms a phylogenetic lineage within the radiation comprising type strains of Mesonia species. The 16S rRNA gene of strain JHPTF-M18^T shared sequence similarities of 97.7% with that of type strain of M. mobilis and 92.5-96.8% with those of type strains of the other nine Mesonia species. The DNA G+C content was 33.1% based on its genomic sequence. AAI, ANI and dDDH values between strain JHPTF-M18^T and the type strains of M. mobilis, M. hitae, M. oceanica, M. phycicola and M. algae were 72.1-83.7%, 73.1-79.7% and 18.5-22.8%, respectively. Strain JHPTF-M18^T contained MK-6 as the predominant menaquinone and iso-C_15:0, iso-C_17:0 3-OH and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) as its major fatty acids. Major polar lipids of strain JHPTF-M18^T were phosphatidylethanolamine and two unidentified lipids. Strain JHPTF-M18^T was separated from recognized Mesonia species by its phenotypic properties together with the phylogenetic and genetic distinctiveness. Based on data presented in this study, strain JHPTF-M18^T is considered to represent a novel species of the genus Mesonia. The name Mesonia aestuariivivens sp. nov. is proposed for JHPTF-M18^T (=KACC 22185^T = NBRC 115119^T).

Priestia veravalensis sp. nov., isolated from coastal sample

The taxonomic position of two isolates, SGD-V-76^T and SGD-M-37, isolated from sediment sample of Veraval coast, India, was examined using the polyphasic taxonomic approach. The morphological and chemotaxonomic characteristics of these two organisms are typical of the genus Priestia. The phylogenetic analyses performed using almost complete 16S rRNA gene sequences demonstrated that the isolate belongs to the Bacillaceae family, and forms a clade within the cluster containing Priestia flexus MTCC 2909^T, Priestia aryabhattai B8W22^T and Priestia megaterium KCTC 3007^T and both strains showed highest similarity of > 98% with 3-29 nucleotide differences. The cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant isoprenoid quinone was MK-7 and the G + C content of strains was 37.5-37.7 mol%. However, the DNA-DNA hybridization and the phenotypic characteristics revealed that, the strain SGD-V-76^T and strain SGD-M-37 are similar species but different from any known Priestia species with ANI values of 79.2, 79.3 and 79.2 and the dDDH values of 17.7, 17.8 and 18.0% respectively. On the basis of phenotypic characteristics, phylogenetic analysis and the results of biochemical and physiological tests, and genomic data strain SGD-V-76^T was clearly distinguished from closely related members of the Priestia genus. Based on the above data analysis strain SGD-V-76^T (= DSM28242^T = KCTC33802^T = CIP111056^T = NCIM5510^T) represents a novel species of the genus Priestia, and we propose the name Priestia veravalensis sp. nov.

Sulfitobacter aestuariivivens sp. nov., isolated from a tidal flat

A Gram-stain-negative, aerobic, non-flagellated, coccoid, ovoid or rod-shaped bacterial strain, TSTF-M16^T, was isolated from a tidal flat on the Yellow Sea, Republic of Korea. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain TSTF-M16^T fell within a clade comprising the type strains of Sulfitobacter species. Strain TSTF-M16^T exhibited 16S rRNA gene sequence similarities of 98.5 and 98.1 % to the type strains of Sulfitobacter mediterraneus and Sulfitobacter sabulilitoris, respectively, and 96.2-97.8 % to the type strains of the other Sulfitobacter species. The average nucleotide identity and digital DNA-DNA hybridization values between the genomic sequences of strain TSTF-M16^T and the type strains of 16 Sulfitobacter species were 70.6-74.2 and 17.9-19.0 %, respectively. The DNA G+C content of strain TSTF-M16^T from genomic sequence data was 59.26 mol%. Strain TSTF-M16^T contained Q-10 as the predominant ubiquinone and C_18 : 1  ω7c as the major fatty acid. The major polar lipids of strain TSTF-M16^T were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. Distinguished phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain TSTF-M16^T is separated from recognized Sulfitobacter species. On the basis of the data presented here, strain TSTF-M16^T is considered to represent a novel species of the genus Sulfitobacter, for which the name Sulfitobacter aestuariivivens sp. nov. is proposed. The type strain is TSTF-M16^T (=KACC 21645^T=NBRC 114501^T).

Kordia aestuariivivens sp. nov. and Olleya sediminilitoris sp. nov., isolated from a tidal flat

Two Gram-stain-negative and non-flagellated bacteria, YSTF-M3^T and YSTF-M6^T, were isolated from a tidal flat from Yellow Sea, Republic of Korea, and subjected to a polyphasic taxonomic study. Neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strains YSTF-M3^T and YSTF-M6^T belong to the genera Kordia and Olleya of the family Flavobacteriaceae, respectively. The 16S rRNA gene sequence similarities between strain YSTF-M3^T and the type strains of Kordia species and between strain YSTF-M6^T and the type strains of Olleya species were 94.1-98.4 and 97.3-98.3 %, respectively. The ANI and dDDH values between genomic sequences of strain YSTF-M3^T and the type strains of five Kordia species and between those of strain YSTF-M6^T and the type strains of three Olleya species were in ranges of 77.0-83.2 and 20.7-27.1 % and 79.4-81.5 and 22.3-23.9 %, respectively. The DNA G+C contents of strain YSTF-M3^T and YSTF-M6^T from genomic sequences were 34.1 and 31.1 %, respectively. Both strains contained MK-6 as predominant menaquinone and phosphatidylethanolamine as only major phospholipid identified. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strains YSTF-M3^T and YSTF-M6^T are separated from recognized species of the genera Kordia and Olleya, respectively. On the basis of the data presented, strains YSTF-M3^T (=KACC 21639^T=NBRC 114499^T) and YSTF-M6^T (=KACC 21640^T=NBRC 114500^T) are considered to represent novel species of the genera Kordia and Olleya, respectively, for which the names Kordia aestuariivivens sp. nov. and Olleya sediminilitoris sp. nov. are proposed.

Qipengyuania soli sp. nov., Isolated from Mangrove Soil

A novel Gram-stain-negative, non-motile, and rod-shaped bacterial strain, designated as 6D36^T, was isolated from mangrove soil and characterized by using a polyphasic taxonomic approach. Strain 6D36^T was found to grow at 10-37 °C (optimum, 28 °C), at pH 6.0-9.0 (optimum, 7.0) and in 0-8% (w/v) NaCl (optimum, 3%). The predominant cellular fatty acids of strain 6D36^T were summed feature 8 (C_19:1 ω7c and/or C_18:1 ω6c) and C_17:1 ω6c; the major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and sphingoglycolipid; the sole respiratory quinone was Q-10. The phylogenetic analysis based on 16S rRNA gene sequences showed that strain 6D36^T fell into the genus Qipengyuania and was closely related to "Erythrobacter mangrovi" MCCC 1K03690^T (98.5%), Qipengyuania citrea CGMCC 1.8703^T (97.6%), and Qipengyuania pelagi JCM 17468^T (97.4%). The phylogenomic analysis indicated that strain 6D36^T formed an independent branch distinct from reference-type strains of species within this genus. The digital DNA-DNA hybridization and average nucleotide identity values between strain 6D36^T and the three type strains above were, respectively, 20.2-21.3% and 79.5-81.5%, of which were far below their respective threshold for species definition, implying that the strain represents a novel genospecies. The genomic DNA G + C content was 63.3%. Based on phenotypic and genotypic characteristics, strain 6D36^T is concluded to represent a novel species of the genus Qipengyuania, for which the name Qipengyuania soli sp. nov., is proposed. The type strain of the species is 6D36^T (= GDMCC 1.1977^T = KCTC 82333^T).

Carotenoids produced by the deep-sea bacterium Erythrobacter citreus LAMA 915: detection and proposal of their biosynthetic pathway

Technologies based on synthetic biology to produce bacterial natural carotenoids depend on information regarding their biosynthesis. Although the biosynthetic pathway of common carotenoids is known, there are carotenoids whose pathways are not completely described. This work aimed to mine the genome of the deep-sea bacterium Erythrobacter citreus LAMA 915, an uncommon bacterium that forms yellow colonies under cultivation. This work further explores the potential application of the carotenoids found and low-cost substrates for bacterial growth. A combined approach of genome mining and untargeted metabolomics analysis was applied. The carotenoid erythroxanthin sulfate was detected in E. citreus LAMA 915 cell extract. A proposal for carotenoid biosynthesis by this bacterium is provided, involving the genes crtBIYZWG. These are responsible for the biosynthesis of carotenoids from the zeaxanthin pathway and their 2,2'-hydroxylated derivatives. E. citreus LAMA 915 extracts showed antioxidant and sun protection effects. Based on the high content of proteases and lipases, it was possible to rationally select substrates for bacterial growth, with residual oil from fish processing the best low-cost substrate selected. This work advances in the understanding of carotenoid biosynthesis and provides a genetic basis that can be further explored as a biotechnological route for carotenoid production.

Arenibacter arenosicollis sp. nov., isolated from a sand dune

A Gram-stain-negative, aerobic, non-spore-forming, non-motile and rod-shaped bacterial strain, designated BSSL-BM3^T, was isolated from sand collected from a dune near the Yellow Sea, Republic of Korea, and subjected to a polyphasic taxonomic study. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain BSSL-BM3^T fell within the clade comprising the type strains of Arenibacter species. Strain BSSL-BM3^T exhibited 16S rRNA gene sequence similarity values of 98.0-99.0 % to the type strains of Arenibacter catalasegens, Arenibacter hampyeongensis, Arenibacter echinorum, Arenibacter palladensis and Arenibacter troitsensis and of 94.2-96.7 % to the type strains of the other Arenibacter species. The averagenucleotide identity and digitalDNA-DNA hybridization values between strain BSSL-BM3^T and the type strains of A. catalasegens, A. hampyeongensis, A. echinorum, A. palladensis and A. troitsensis were 82.2-88.8 % and 25.0-36.5 %, respectively. The DNA G+C content of strain BSSL-BM3^T from genomic sequence data was 38.75 mol%. Strain BSSL-BM3^T contained MK-6 as the predominant menaquinone and iso-C_17 : 0 3-OH, summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) and iso-C_15 : 1 G as the major fatty acids. The major polar lipids of strain BSSL-BM3^T were phosphatidylethanolamine and two unidentified lipids. Distinguishing phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that strain BSSL-BM3^T is separated from recognized Arenibacter species. On the basis of the data presented here, strain BSSL-BM3^T is considered to represent a novel species of the genus Arenibacter, for which the name Arenibacter arenosicollis sp. nov. is proposed. The type strain is BSSL-BM3^T (=KACC 21632^T=NBRC 114502^T).

Real-Time Culture-Independent Microbial Profiling Onboard the International Space Station Using Nanopore Sequencing

For the past two decades, microbial monitoring of the International Space Station (ISS) has relied on culture-dependent methods that require return to Earth for analysis. This has a number of limitations, with the most significant being bias towards the detection of culturable organisms and the inherent delay between sample collection and ground-based analysis. In recent years, portable and easy-to-use molecular-based tools, such as Oxford Nanopore Technologies' MinION™ sequencer and miniPCR bio's miniPCR™ thermal cycler, have been validated onboard the ISS. Here, we report on the development, validation, and implementation of a swab-to-sequencer method that provides a culture-independent solution to real-time microbial profiling onboard the ISS. Method development focused on analysis of swabs collected in a low-biomass environment with limited facility resources and stringent controls on allowed processes and reagents. ISS-optimized procedures included enzymatic DNA extraction from a swab tip, bead-based purifications, altered buffers, and the use of miniPCR and the MinION. Validation was conducted through extensive ground-based assessments comparing current standard culture-dependent and newly developed culture-independent methods. Similar microbial distributions were observed between the two methods; however, as expected, the culture-independent data revealed microbial profiles with greater diversity. Protocol optimization and verification was established during NASA Extreme Environment Mission Operations (NEEMO) analog missions 21 and 22, respectively. Unique microbial profiles obtained from analog testing validated the swab-to-sequencer method in an extreme environment. Finally, four independent swab-to-sequencer experiments were conducted onboard the ISS by two crewmembers. Microorganisms identified from ISS swabs were consistent with historical culture-based data, and primarily consisted of commonly observed human-associated microbes. This simplified method has been streamlined for high ease-of-use for a non-trained crew to complete in an extreme environment, thereby enabling environmental and human health diagnostics in real-time as future missions take us beyond low-Earth orbit.

Pseudoalteromonas caenipelagi sp. nov., isolated from a tidal flat

A Gram-stain-negative, aerobic, non-spore-forming, motile by single polar flagellum and ovoid or rod-shaped bacterial strain, designated JBTF-M23^T, was isolated from tidal flat sediment collected from the Yellow Sea, Republic of Korea. Neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain JBTF-M23^T fell within the clade comprising the type strains of Pseudoalteromonas species, clustering with the type strains of P. byunsanensis and P. amylolytica. Strain JBTF-M23^T exhibited the highest 16S rRNA gene sequence similarity value (98.6 %) to the type strain of P. rubra and sequence similarities of 98.3 and 97.7 % to the type strains of P. byunsanensis and P. amylolytica, respectively. The DNA G+C content of strain JBTF-M23^T from genomic sequence data was 41.98 %. The ANI and dDDH values between strain JBTF-M23^T and the type strains of P. rubra, P. byunsanensis and P. amylolytica were 71.3-76.6 and 19.4-19.9 %, respectively. Strain JBTF-M23^T contained Q-8 as the predominant ubiquinone and C_16 : 1  ω7c and/or C_16 : 1  ω6c, C_16 : 0 and C_18 : 1  ω7c as the major fatty acids. The major polar lipids of strain JBTF-M23^T were phosphatidylethanolamine and one unidentified aminolipid. Distinguished phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that strain JBTF-M23^T is separated from recognized Pseudoalteromonas species. On the basis of the data presented, strain JBTF-M23^Tis considered to represent a novel species of the genus Pseudoalteromonas, for which the name Pseudoalteromonas caenipelagi sp. nov. is proposed. The type strain is JBTF-M23^T(=KACC 19900^T=NBRC 113647^T).

Aurantiacibacter rhizosphaerae sp. nov., isolated from a rhizosphere mudflat of a halophyte and proposal to reclassify Erythrobacter suaedae Lee et al. 2019. and Erythrobacter flavus Yoon et al. 2003 as Aurantiacibacter suaedae comb. nov. and Qipengyuania flava comb. nov., respectively

A marine alphaproteobacterium, designated as strain GH3-10^T, was isolated from the rhizosphere mud of a halophyte (Suaeda japonica) collected at the seashore of Gangwha Island, Republic of Korea. The isolate was found to be Gram-stain-negative, strictly aerobic, catalase- and oxidase-positive, non-motile, short rods and produced orange-coloured colonies. The 16S rRNA gene- and whole genome-based phylogenetic analyses exhibited that strain GH3-10^T belonged to the genus Aurantiacibacter and was most closely related to Aurantiacibacter atlanticus s21-N3^T (98.7 % 16S rRNA gene sequence similarity) and Aurantiacibacter marinus KCTC 23554^T (98.4 %). The major respiratory quinone was ubiquinone-10. The polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid and an unidentified lipid. The major fatty acids were C_18 : 1  ω7c, summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) and C_18 : 1  ω7c 10-methyl. The DNA G+C content was 61.3 mol% (by genome). Average nucleotide identity and DNA-DNA relatedness values between the isolate and its phylogenetically closest relatives, together with phenotypic distinctness warranted the taxonomic description of a new species. On the basis of data obtained by a polyphasic approach, strain GH3-10^T (=KCTC 62379^T=JCM 32444^T) represents a novel species of the genus Aurantiacibacter, for which the name Aurantiacibacter rhizosphaerae sp. nov. is proposed. According to phylogenetic coherence based on 16S rRNA genes and core genomes, it is also proposed that Erythrobacter suaedae Lee et al. 2019. and Erythrobacter flavus Yoon et al. 2003 be transferred to Aurantiacibacter suaedae comb. nov. and Qipengyuania flava comb. nov., respectively.

Alteromonas ponticola sp. nov., a gammaproteobacterium isolated from seawater

A Gram-stain-negative, aerobic, non-spore-forming, non-motile and ovoid or rod-shaped bacterial strain, MYP5T, was isolated from seawater in Jeju island of South Korea. MYP5T grew optimally at 30–35 °C and in the presence of 2.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that MYP5T fell within the clade enclosed by the type strains of species of the genus Alteromonas , clustering with the type strains of Alteromonas confluentis and Alteromonas halophila . MYP5T exhibited the highest 16S rRNA gene sequence similarity value (98.0 %) to the type strain of A. confluentis and similarities of 95.1–97.9 % to the type strains of the other species of the genus Alteromonas . ANI and dDDH values of genomic sequences between MYP5T and the type strains of 22 species of the genus Alteromonas were 66.8–70.5 % and 18.6–27.5 %, respectively. The DNA G+C content of MYP5T, determined from the genome sequence, was 46.1 %. MYP5T contained Q-8 as the predominant ubiquinone and C18 : 1 ω7c, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and 10-methyl C17 : 0 as the major fatty acids. The major polar lipids of MYP5T were phosphatidylethanolamine and phosphatidylglycerol. Distinguishing phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that MYP5T is separated from species of the genus Alteromonas . On the basis of the data presented, MYP5T is considered to represent a novel species of the genus Alteromonas , for which the name Alteromonas ponticola sp. nov. is proposed. The type strain is MYP5T (=KCTC 82144T=NBRC 114354T).

Description of Shewanella salipaludis sp. nov., isolated from a salt marsh

A Gram-stain-negative and flagellated bacterial strain, SHSM-M6T, was isolated from salt marsh from Yellow Sea, Republic of Korea. Neighbor-joining phylogenetic tree of 16S rRNA gene sequences showed that strain SHSM-M6T belongs to the genus Shewanella. 16S rRNA gene sequence similarity values between strain SHSM-M6T and the type strains of Shewanella species were <98.0%. The average nucleotide identity and DNA-DNA hybridization values between genomic sequences of strain SHSM-M6T and the type strains of Shewanella species were <73.3 and 20.7%, respectively. Strain SHSM-M6T contained MK-6 as predominant menaquinone and Q-7 and Q-8 as the predominant ubiquinones. The novel strain contained C16:1ω7c and/or C16:1ω6c, iso-C15:0 and C16:0 as major fatty acids. Major polar lipids of strain SHSM-M6T were phosphatidylethanolamine, phosphatidylglycerol, one unidentified lipid, one unidentified aminolipid and one unidentified phospholipid. Differential phenotypic properties of strain SHSM-M6T, together with its phylogenetic and genetic distinctiveness, revealed that strain SHSM-M6T is separated from recognized Shewanella species. On the basis of the data presented, strain SHSM-M6T is considered to represent a novel species of the genus Shewanella, for which the name Shewanella salipaludis sp. nov. is proposed. The type strain is SHSM-M6T (=KACC 19901T = NBRC 113646T).

Shewanella insulae sp. nov., isolated from a tidal flat

A Gram-stain-negative, aerobic, non-spore-forming, motile by single polar flagellum and ovoid or rod-shaped bacterial strain, designated JBTF-M18^T, was isolated from tidal-flat sediment collected from the Yellow Sea, Republic of Korea. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain JBTF-M18^T fell within the clade comprising the type strains of Shewanella species. Strain JBTF-M18^T exhibited 16S rRNA gene sequence similarity values of 97.1-98.8 % to the type strains of S. loihica, S. aquimarina, S. waksmanii and S. marisflavi and of less than 96.9 % to the type strains of the other Shewanella species. The average nucleotide identity and digital DNA-DNA hybridization values between strain JBTF-M18^T and the type strains of S. waksmanii and S. loihica were 72.0 and 89.5% and 18.9 and 38.1 %, respectively. DNA-DNA relatedness values between strain JBTF-M18^T and the type strains of S. aquimarina and S. marisflavi were 14 and 19 %, respectively. The DNA G+C content of strain JBTF-M18^T from genomic sequence data was 52.9 %. Strain JBTF-M18^Tcontained MK-6 as the predominant menaquinone and Q-7 and Q-8 as the predominant ubiquinones. It had iso-C_15 : 0, summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) and C_16 : 0 as the major fatty acids. The major polar lipids of strain JBTF-M18^T were phosphatidylethanolamine and phosphatidylglycerol. Distinguished phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that strain JBTF-M18^T is separated from recognized Shewanella species. On the basis of the data presented, strain JBTF-M18^T is considered to represent a novel species of the genus Shewanella, for which the name Shewanella insulae sp. nov. is proposed. The type strain is JBTF-M18^T (=KACC 19869^T=NBRC 113583^T).

Description of Sulfitobacter sediminilitoris sp. nov., isolated from a tidal flat

A Gram-stain-negative bacterial strain, JBTF-M27T, was isolated from a tidal flat from Yellow Sea, Republic of Korea. Neighbor-joining phylogenetic tree of 16S rRNA gene sequences showed that strain JBTF-M27T fell within the clade comprising the type strains of Sulfitobacter species. Strain JBTF-M27T exhibited the highest 16S rRNA gene sequence similarity (98.8%) to the type strain of S. porphyrae. Genomic ANI and dDDH values of strain JBTF-M27T between the type strains of Sulfitobacter species were less than 76.1 and 19.2%, respectively. Mean DNA-DNA relatedness value between strain JBTF-M27T and the type strain of S. porphyrae was 21%. DNA G + C content of strain JBTF-M27T from genome sequence was 57.8% (genomic analysis). Strain JBTF-M27T contained Q-10 as the predominant ubiquinone and C18:1ω7c as the major fatty acid. The major polar lipids of strain JBTF-M27T were phosphatidylcholine, phosphatidylglycerol and one unidentified aminolipid. Distinguished phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that strain JBTF-M27T is separated from recognized Sulfitobacter species. On the basis of the data presented, strain JBTF-M27T ( = KACC 21648T = NBRC 114356T) is considered to represent a novel species of the genus Sulfitobacter, for which the name Sulfitobacter sediminilitoris sp. nov. is proposed.

Erythrobacter insulae sp. nov., isolated from a tidal flat

A Gram-staining-negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated as JBTF-M21T, was isolated from a tidal flat sediment on the Yellow Sea, Republic of Korea. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences indicated that JBTF-M21T fell within the clade comprising the type strains of species of the genus Erythrobacter . JBTF-M21T exhibited 16S rRNA gene sequence similarities of 97.0–98.4 % to the type strains of Erythrobacter longus , Erythrobacter aquimaris , Erythrobacter nanhaisediminis , Erythrobacter vulgaris , Erythrobacter seohaensis , Erythrobacter litoralis and Erythrobacter citreus and 93.7–96.6 % to the type strains of the other species of the genus Erythrobacter . The ANI and dDDH values between JBTF-M21T and the type strains of E. longus , E. nanhaisediminis , E. seohaensis and E. litoralis were 70.83–72.93 % and 18.0–18.8 %, respectively. Mean DNA–DNA relatedness values between JBTF-M21T and the type strains of E. aquimaris , E. vulgaris and E. citreus were 12–24 %. The DNA G+C content of JBTF-M21T was 57.0 mol%. JBTF-M21T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c and C17 : 1ω6c as the major fatty acids. The major polar lipids ofJBTF-M21T were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and sphingoglycolipid. Distinguishing phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that JBTF-M21T is separated from species of the genus Erythrobacter with validly published names. On the basis of the data presented, strain JBTF-M21T is considered to represent a novel species of the genus Erythrobacter , for which the name Erythrobacter insulae sp. nov. is proposed. The type strain is JBTF-M21T (=KACC 19864T=NBRC 113584T).

Gramella sabulilitoris sp. nov., isolated from a marine sand

A Gram-stain-negative, aerobic, non-spore-forming, motile by gliding and rod-shaped bacterial strain, designated HSMS-1^T, was isolated from a marine sand collected from the Yellow Sea, Republic of Korea, and identified by a polyphasic taxonomic approach. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that HSMS-1^T fell within the clade comprising the type strains of species of the genus Gramella. HSMS-1^T exhibited 16S rRNA gene sequence similarity values of 99.0 and 98.7 % to the type strains of Gramella echinicola and Gramella sediminilitoris and of 93.3-98.5 % to the type strains of the other species of the genus Gramella. The ANI and dDDH values between HSMS-1^T and the type strains of G. echinicola, Gramella gaetbulicola, Gramella forsetii, Gramella salexigens, Gramella portivictoriae and Gramella flava were 72.6-79.3 % and 17.4-22.2 %, respectively. Mean DNA-DNA relatedness value between HSMS-1^T and the type strain of G. sediminilitoris was 18 %. HSMS-1^T contained MK-6 as the predominant menaquinone and iso-C_15 : 0, anteiso-C_15 : 0, iso-C_17 : 0 3-OH and iso-C_16 : 0 as the major fatty acids. The major polar lipid of HSMS-1^T was phosphatidylethanolamine. The DNA G+C content of HSMS-1^T from genomic sequence data was 39.2 %. Distinguishing phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that HSMS-1^T is separated from recognized species of the genus Gramella. On the basis of the data presented, strain HSMS-1^T is considered to represent a novel species of the genus Gramella, for which the name Gramella sabulilitoris sp. nov. is proposed. The type strain is HSMS-1^T(=KACC 19899^T=NBRC 113648^T).

Sulfur-Containing Carotenoids from A Marine Coral Symbiont Erythrobacter flavus Strain KJ5

Erythrobacter flavus strain KJ5 (formerly called Erythrobacter sp. strain KJ5) is a yellowish marine bacterium that was isolated from a hard coral Acropora nasuta in the Karimunjawa Islands, Indonesia. The complete genome sequence of the bacterium has been reported recently. In this study, we examined the carotenoid composition of this bacterium using high-performance liquid chromatography coupled with ESI-MS/MS. We found that the bacterium produced sulfur-containing carotenoids, i.e., caloxanthin sulfate and nostoxanthin sulfate, as the most abundant carotenoids. A new carotenoid zeaxanthin sulfate was detected based on its ESI-MS/MS spectrum. The unique presence of sulfated carotenoids found among the currently known species of the Erythrobacter genus were discussed.

Quorum-Quenching Bacteria Isolated From Red Sea Sediments Reduce Biofilm Formation by Pseudomonas aeruginosa

Quorum sensing (QS) is the process by which bacteria communicate with each other through small signaling molecules such as N-acylhomoserine lactones (AHLs). Certain bacteria can degrade AHL molecules by a process called quorum quenching (QQ); therefore, QQ can be used to control bacterial infections and biofilm formation. In this study, we aimed to identify new species of bacteria with QQ activity. Red Sea sediments were collected either from the close vicinity of seagrass or from areas with no vegetation. We isolated 72 bacterial strains, which were tested for their ability to degrade/inactivate AHL molecules. Chromobacterium violaceum CV026-based bioassay was used for the initial screening of isolates with QQ activity. QQ activity was further quantified using high-performance liquid chromatography-tandem mass spectrometry. We found that these isolates could degrade AHL molecules of different acyl chain lengths as well as modifications. 16S-rRNA sequencing of positive QQ isolates showed that they belonged to three different genera. Specifically, two isolates belonged to the genus Erythrobacter; four, Labrenzia; and one, Bacterioplanes. The genome of one representative isolate from each genus was sequenced, and potential QQ enzymes, namely, lactonases and acylases, were identified. The ability of these isolates to degrade the 3OXOC12-AHLs produced by Pseudomonas aeruginosa PAO1 and hence inhibit biofilm formation was investigated. Our results showed that the isolate VG12 (genus Labrenzia) is better than other isolates at controlling biofilm formation by PAO1 and degradation of different AHL molecules. Time-course experiments to study AHL degradation showed that VG1 (genus Erythrobacter) could degrade AHLs faster than other isolates. Thus, QQ bacteria or enzymes can be used in combination with an antibacterial to overcome antibiotic resistance.

Diversity of culturable bacteria in deep-sea water from the South Atlantic Ocean

The variability of culturable bacterial diversity and distribution was studied by phylogenetic analysis of 16S rRNA sequences. Seventeen water samples were examined and were collected, from different depths in the range of 5 m to 2700 m at 3 sampling sites (CTD06, CTD10 and CTD11) in the South Atlantic Ocean. Phylogenetic analysis of 16S rRNA gene sequences revealed a significant diversity of culturable bacteria. A total of 247 strains clustered into 8 classes: γ-Proteobacteria, α-Proteobacteria, Actinobacteria, Actinomycetales, Bacilli, Flavobacteria, Opitutae and Sphingobacteria. The 17 water samples were dominated by populations of strains belonging to the genus Erythrobacter (16.60%). Of the 247 strains, 10 were potential new species and might form a minor population in the deep sea. To our knowledge, this is the first report to analyze the diversity of culturable bacteria in the South Atlantic Ocean from different depths across the water column.

Erythrobacter atlanticus sp. nov., a bacterium from ocean sediment able to degrade polycyclic aromatic hydrocarbons

A Gram-stain-negative, motile, rod-shaped, orange-pigmented bacterium able to degrade polycyclic aromatic hydrocarbons was isolated from deep-sea sediment of the Atlantic Ocean and subjected to a polyphasic taxonomic study. The strain, designated s21-N3T, could grow at 4–37 °C (optimum 28 °C), at pH 5–10 (optimum pH 7–8) and with 1–7 % (w/v) NaCl (optimum 2–3 %). Strain s21-N3T was positive for nitrate reduction, denitrification, aesculin hydrolysis, oxidase and catalase, but negative for indole production and urease. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain s21-N3T formed a distinct branch within the genus Erythrobacter, sharing high similarities with three closely related strains, Erythrobacter marinus HWDM-33T (98.67 %), ‘Erythrobacter luteus’ KA37 (97.80 %) and Erythrobacter gangjinensis K7-2T (97.59 %). The similarities between strain s21-N3T and other type strains of recognized species within the genus Erythrobacter ranged from 95.00 to 96.47 %. The digital DNA–DNA hybridization values and average nucleotide identity (ANI) values between strain s21-N3T and the three closely related strains Erythrobacter marinus HWDM-33T, ‘Erythrobacter luteus’ KA37 and Erythrobacter gangjinensis K7-2T were 18.60, 18.00 and 18.50 % and 74.24, 72.49 and 72.54 %, respectively. The principal fatty acids were summed feature 8 (C18 : 1ω7c/ω6c) and summed feature 3 (C16 : 1ω7c/ω6c). The respiratory lipoquinone was identified as Q-10. The major polar lipids comprised sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and diphosphatidylglycerol. The G+C content of the chromosomal DNA was determined to be 58.18 mol%. The combined genotypic and phenotypic distinctiveness demonstrated that strain s21-N3T represents a novel species of the genus Erythrobacter, for which the name Erythrobacter atlanticus sp. nov. is proposed, with the type strain s21-N3T ( = MCCC 1A00519T = KCTC 42697T).

Erythrobacter luteus sp. nov., isolated from mangrove sediment

A Gram-staining-negative, orange-pigmented, aerobic bacterial strain, designated KA37T, was isolated from a mangrove sediment sample collected from Yunxiao mangrove National Nature Reserve, Fujian Province, China. Growth was observed at 4-37 °C, 0-3% (w/v) NaCl and pH 5-10. Mg2+ ions were required for growth. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that the isolate was a member of the genus Erythrobacter, which belongs to the family Erythrobacteraceae. Strain KA37T was most closely related to Erythrobacter gangjinensis KCTC 22330T (96.9% sequence similarity), followed by Erythrobacter marinus KCTC 23554T (96.8%); similarity to other members of the genus was below 96.6%. The major fatty acids were C17 : 1ω6c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). Strain KA37T did not produce bacteriochlorophyll a. The predominant respiratory quinone was ubiquinone 10 (Q-10). The polar lipids of strain KA37T were sphingoglycolipid, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, five unknown lipids and one unidentified phospholipid. According to its morphology, physiology, fatty acid composition and 16S rRNA sequence, the novel strain most appropriately belongs to the genus Erythrobacter, but can be distinguished readily from species of the genus Erythrobacter with validly published names. The name Erythrobacter luteus sp. nov. is proposed, with strain KA37T ( = MCCC 1F01227T = KCTC 42179T) as the type strain.

Erythrobacter lutimaris sp. nov., isolated from a tidal flat sediment

A Gram-stain-negative, non-motile, coccoid- or oval-shaped bacterial strain, designated S-5T, belonging to the class Alphaproteobacteria , was isolated from a tidal flat sediment of the Yellow Sea, Korea and was subjected to a polyphasic taxonomic study. Strain S-5T grew optimally at pH 7.0–8.0, at 30 °C and in the presence of 2–3 % (w/v) NaCl. Neighbour-joining analysis based on 16S rRNA gene sequences showed that strain S-5T fell within the clade comprising the species of the genus Erythrobacter , clustering with the type strains of Erythrobacter pelagi , Erythrobacter citreus and Erythrobacter seohaensis with which it exhibited the highest 16S rRNA gene sequence similarity (96.0–96.7 %). The DNA G+C content was 66.0 mol%. Strain S-5T contained Q-10 as the predominant ubiquinone and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C17 : 1ω6c as the major fatty acids. The major polar lipids were sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol, an unidentified glycolipid and two unidentified lipids. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, demonstrated that strain S-5T is distinguishable from other species of the genus Erythrobacter . On the basis of the data presented, strain S-5T is considered to represent a novel species of the genus Erythrobacter , for which the name Erythrobacter lutimaris sp. nov. is proposed. The type strain is S-5T ( = KCTC 42109T = CECT 8624T).

Erythrobacter jejuensis sp. nov., isolated from seawater

A Gram-staining-negative, yellow-pigmented, non-motile, strictly aerobic, rod-shaped bacterium, designated strain CNU001T, was isolated from seawater collected on the coast of Jeju Island, South Korea, and subjected to a polyphasic taxonomic study. The temperature, pH and NaCl ranges for growth were 10–30 °C, pH 6.0–10.0 and 2.0–5.0 %, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain CNU001T belonged to the genus Erythrobacter in the family Erythrobacteraceae , with Erythrobacter longus DSM 6997T (96.6 % sequence similarity), Erythrobacter gaetbuli SW-161T (96.3 %), Erythrobacter vulgaris 022 2-10T (96.2 %), Erythrobacter nanhaisediminis T30T (96.1 %) and other members of the genus Erythrobacter (<96.0 %) identified as the novel strain’s closest relatives. The major cellular fatty acids were C18 : 1ω7c and C17 : 1ω6c. The polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, one sphingoglycolipid, one unidentified aminolipid and six other unidentified lipids. The major respiratory quinone was ubiquinone-10 (UQ-10) and the genomic DNA G+C content of the novel strain was 58.9 mol%. On the basis of phenotypic, phylogenetic and genotypic data, strain CNU001T represents a novel species within the genus Erythrobacter , for which the name Erythrobacter jejuensis sp. nov. is proposed. The type strain is CNU001T ( = KCTC 23090T  = JCM 16677T).

Erythrobacter westpacificensis sp. nov., a marine bacterium isolated from the Western Pacific

A novel Gram-negative, orange-pigmented bacterial strain JLT2008(T) was isolated from the surface seawater of the Western Pacific and subjected to a polyphasic taxonomic study. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain JLT2008(T) belonged to the genus Erythrobacter, sharing the highest similarity (96.6 %) with Erythrobacter gangjinensis K7-2(T) and the lowest similarity (94.9 %) with Erythrobacter litoralis DSM 8509(T). Strain JLT2008(T) did not contain bacteriochlorophyll a, and the predominant respiratory lipoquinone was ubiquinone-10. The major fatty acids were C(18:1) ω7c, C(16:0), C(16:1) ω7c/C(16:1) ω6c. The prominent polar lipids were sphingoglycolipid, phosphatidylethanolamine, and phosphatidylglycerol. The genomic G + C content was 60.1 mol %. Based on the polyphasic taxonomic data, a novel species within the genus Erythrobacter, and with the name Erythrobacter westpacificensis sp. nov., is proposed. The type strain is JLT2008(T) (=CGMCC 1.10993(T) = JCM 18014(T)).

Erythrobacter marinus sp. nov., isolated from seawater

A Gram-negative, non-motile, ovoid to rod-shaped bacterium, designated strain HWDM-33T, was isolated from seawater of the Yellow Sea, Korea, and was subjected to a polyphasic taxonomic study. Strain HWDM-33T grew optimally at pH 7–8, at 25 °C and in the presence of 2–3 % (w/v) NaCl. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences showed that strain HWDM-33T clustered with Erythrobacter gangjinensis K7-2T, with which it shared 96.9 % sequence similarity. Strain HWDM-33T exhibited 94.2–95.8 % 16S rRNA gene sequence similarity to the type strains of other recognized species of the genus Erythrobacter . Strain HWDM-33T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c, C17 : 1ω6c, and C16 : 1ω7c and/or iso-C15 : 0 2-OH as the major fatty acids. The major polar lipids were sphingoglycolipid, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and an unidentified lipid. The DNA G+C content of strain HWDM-33T was 66.1 mol%. Differential phenotypic properties and phylogenetic distinctiveness demonstrated that strain HWDM-33T was separate from E. gangjinensis and other recognized species of the genus Erythrobacter . On the basis of the data presented here, strain HWDM-33T represents a novel species of the genus Erythrobacter , for which the name Erythrobacter marinus sp. nov. is proposed. The type strain is HWDM-33T ( = KCTC 23554T  = CCUG 60528T).

Erythrobacter pelagi sp. nov., a member of the family Erythrobacteraceae isolated from the Red Sea

A novel Gram-negative, aerobic, catalase- and oxidase-positive, non-sporulating, non-motile, rod-shaped bacterium, designated strain UST081027-248(T), was isolated from seawater of the Red Sea. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain UST081027-248(T) fell within the genus Erythrobacter. Levels of 16S rRNA gene sequence similarity between the novel strain and the type strains of Erythrobacter species ranged from 95.3 % (with Erythrobacter gangjinensis) to 98.2 % (with Erythrobacter citreus). However, levels of DNA-DNA relatedness between strain UST081027-248(T) and the type strains of closely related species were below 70 %. Optimal growth of the isolate occurred in the presence of 2.0 % NaCl, at pH 8.0-9.0 and at 28-36 °C. The isolate did not produce bacteriochlorophyll a. The predominant cellular fatty acids were C(17:1)ω6c, summed feature 8 (C(18:1)ω6c and/or C(18:1)ω7c) and C(15:0) 2-OH. The genomic DNA G+C content of strain UST081027-248(T) was 60.4 mol%. Phenotypic properties and phylogenetic distinctiveness clearly indicated that strain UST081027-248(T) represents a novel species of the genus Erythrobacter, for which the name Erythrobacter pelagi sp. nov. is proposed. The type strain is UST081027-248(T) ( = JCM 17468(T) = NRRL 59511(T)).

Erythrobacter nanhaisediminis sp. nov., isolated from marine sediment of the South China Sea

A novel Gram-negative, orange-pigmented, slightly halophilic, rod-shaped bacterium, strain T30(T), was isolated from sediment from the South China Sea. Phylogenetic analysis showed that strain T30(T) was a member of the genus Erythrobacter, sharing highest 16S rRNA gene sequence similarities with Erythrobacter aquimaris JCM 12189(T) (99.5 %) and Erythrobacter vulgaris DSM 17792(T) (99.0 %). Levels of DNA-DNA relatedness between strain T30(T) and closely related strains of Erythrobacter species ranged from 14.5 to 56.9 %.The isolate lacked bacteriochlorophyll a and contained ubiquinone-10 as the predominant respiratory lipoquinone. The major fatty acids of this strain were C(18 : 1) ω(38.2 %) and C(16 : 1) ω 7c /C(16 : 1) ω 6c (17.4 %). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine and phosphatidylglycerol. The DNA G+C content of strain T30(T) was 59.5 mol%. On the basis of phenotypic and phylogenetic data, a novel species, Erythrobacter nanhaisediminis sp. nov., is proposed; the type strain is T30(T) (=CGMCC 1.7715(T)=JCM 16125(T)).

Erythrobacter gangjinensis sp. nov., a marine bacterium isolated from seawater

A novel Gram-negative, aerobic, orange-pigmented bacterial strain, designated K7-2(T), was isolated from seawater of Gangjin Bay, Korea, and subjected to a polyphasic taxonomic study. Strain K7-2(T) contained ubiquinone-10 (Q-10) as the predominant respiratory lipoquinone and did not produce bacteriochlorophyll a. Major fatty acids were C(18 : 1)omega7c (51.4 %), iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c (15.0 %) and C(17 : 1)omega6c (8.8 %). Major polar lipids were phosphatidylethanolamine and phosphatidylcholine. The DNA G+C content was 61.6 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain K7-2(T) formed a distinct phylogenetic lineage within the cluster comprising Erythrobacter strains. Similarities between the 16S rRNA gene sequences of strain K7-2(T) and the type strains of Erythrobacter species ranged from 95.0 % (Erythrobacter litoralis DSM 8509(T)) to 96.8 % (Erythrobacter citreus RE35F/1(T)). On the basis of polyphasic taxonomic data, strain K7-2(T) (=KCTC 22330(T)=JCM 15420(T)) is classified in a novel species within the genus Erythrobacter, for which the name Erythrobacter gangjinensis sp. nov. is proposed.

Altererythrobacter marinus sp. nov., isolated from deep seawater

A taxonomic study was carried out on strain H32(T), which was isolated from a crude-oil-degrading consortium enriched from deep seawater of the Indian Ocean. The 16S rRNA gene sequence of strain H32(T) showed highest similarity to that of Altererythrobacter luteolus SW-109(T) (96.7 %); lower similarities were observed with other members of the genus Altererythrobacter (94.7-95.7 %) and with members of the genera Erythrobacter (94.5-96.3 %), Erythromicrobium (94.9 %) and Porphyrobacter (94.3-95.3 %). Phylogenetic analyses of all members of the family Erythrobacteraceae and several members of the family Sphingomonadaceae revealed that strain H32(T) formed a clade within the genus Altererythrobacter. The dominant fatty acids were C(16 : 0) (6.7 %), C(18 : 1)omega7c (44.3 %) and 11-methyl C(18 : 1)omega7c (25.4 %). The major respiratory quinone was ubiquinone 10. The DNA G+C content was 66.5 mol%. Strain H32(T) did not contain bacteriochlorophyll a. These characteristics are in good agreement with those of members of the genus Altererythrobacter. Therefore, according to its morphology, physiology, fatty acid composition and 16S rRNA gene sequence data, strain H32(T) belongs to the genus Altererythrobacter, but can be readily distinguished from known Altererythrobacter species. It is therefore proposed that strain H32(T) represents a novel species, Altererythrobacter marinus sp. nov., with H32(T) (=CCTCC AB 208229(T) =LMG 24629(T) =MCCC 1A01070(T)) as the type strain.

Complete genome sequence of Erythrobacter litoralis HTCC2594

Erythrobacter litoralis has been known as a bacteriochlorophyll a-containing, aerobic, anoxygenic, phototrophic bacterium. Here we announce the complete genome sequence of E. litoralis HTCC2594, which is devoid of phototrophic potential. E. litoralis HTCC2594, isolated by dilution-to-extinction culturing from seawater, could not carry out aerobic anoxygenic phototrophy and lacked genes for bacteriochlorophyll a biosynthesis and photosynthetic reaction center proteins.

Altererythrobacter indicus sp. nov., isolated from wild rice (Porteresia coarctata Tateoka)

A Gram-negative, rod-shaped, non-spore-forming organism, strain MSSRF26T, was isolated from mangrove-associated wild rice in India. On the basis of 16S rRNA gene sequence similarities, strain MSSRF26T was shown to belong to the Alphaproteobacteria, most closely related to Altererythrobacter luteolus and Altererythrobacter epoxidivorans (96.1 and 95.9 % similarity to the respective type strains). Chemotaxonomic data [major ubiquinones Q-10 (91 %) and Q-9 (9 %); major polyamine spermidine, with putrescine, cadaverine and spermine detected only in trace amounts; major polar lipids phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and sphingoglycolipid; major fatty acid C18 : 1 omega 7c and C(14 : 0) 2-OH as hydroxylated fatty acid] supported the affiliation of MSSRF26T to the genus Altererythrobacter. Fatty acid data and physiological and biochemical tests allowed phenotypic differentiation of the isolate from described Altererythrobacter species. Strain MSSRF26T therefore represents a novel species, for which the name Altererythrobacter indicus sp. nov. is proposed, with the type strain MSSRF26T (=LMG 23789T =DSM 18604T).

Screening enantioselective epoxide hydrolase activities from marine microorganisms: detection of activities in Erythrobacter spp

To develop an enantioselective epoxide hydrolase (EHase) from marine microorganisms, marine samples were collected from a variety of marine environments. Strains isolated by the capability of living on styrene oxide (SO) were screened for retaining enantioselective EHase activities toward SO by combining spectrophotometric, GC, and HPLC analysis. Consequently, one strain, JCS358, was selected, and the sequence analysis of 16S rRNA gene showed that the strain belonged to Erythrobacter cluster. Twelve additional Erythrobacter strains from this study or acquired from culture collections were thereby tested for displaying EHase activities, and most of tested strains showed enantioselective hydrolysis toward SO and glycidyl phenyl ether. Kinetic resolution of racemic SO using whole cell of Erythrobacter sp. JCS358 was performed. Enantiopure (S)-SO could be obtained with an enantiomeric excess (ee) higher than 99% after 15 h incubation. The determination of 1-phenyl-1,2-ethanediol configuration derived from racemic SO confirmed the enantioselective hydrolyzing activity of Erythrobacter sp. JCS358.