• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1428-1436
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• 2023

The three Gram-negative, catalase- and oxidase-positive bacterial strains RS43^T, HBC28, and HBC61^T, were isolated from fresh water and subjected to a polyphasic study. Comparison of 16S rRNA gene sequence initially indicated that strains RS43^T, HBC28, and HBC61^T were closely related to species of genus Curvibacter and shared the highest sequence similarity of 98.14%, 98.21%, and 98.76%, respectively, with Curvibacter gracilis 7-1^T. Phylogenetic analysis based on genome sequences placed all strains within the genus Curvibacter. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the three strains and related type strains supported their recognition as two novel genospecies in the genus Curvibacter. Comparative genomic analysis revealed that the genus possessed an open pangenome. Based on KEGG BlastKOALA analyses, Curvibacter species have the potential to metabolize benzoate, phenylacetate, catechol, and salicylate, indicating their potential use in the elimination of these compounds from the water systems. The results of polyphasic characterization indicated that strain RS43^T and HBC61^T represent two novel species, for which the name Curvibacter microcysteis sp. nov. (type strain RS43^T =KCTC 92793^T=LMG 32714^T) and Curvibacter cyanobacteriorum sp. nov. (type strain HBC61^T =KCTC 92794^T=LMG 32713^T) are proposed.

• Journal of Species Research
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• v.8 no.2
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• pp.191-196
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• 2019

In 2015 and 2017, the National Institute of Biological Resources has isolated four unrecorded prokaryotic species designated as R-1-5, R-2-13, R-2-1, and R-1-8 from the peatland soil of Yongneup. Phylogenetic analysis based on 16S rRNA gene sequence similarity determined the four strains (R-1-5, R-2-13, R-2-1, R-1-8) were most closely related to Curvibacter lanceolatus (99.93%), Massilia brevitalea (98.7%), Pseudomonas lini (99.54%), and Pseudomonas vancouverensis (99.93%), respectively. The four unrecorded strains belong to the phylum Proteobacteria, in which the genera Curvibacter and Massilia are assigned to the class Betaproteobacteria, and the genus Pseudomonas to the class Gammaproteobacteria. Since there are no publications or official reports on these four strains, these four species are new records to Korea. The strains were further characterized by Gram reaction, colony and cell morphology, basic biochemical properties, and phylogenetic position. Descriptive information of the four unrecorded species is provided.

• Journal of Species Research
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• v.6 no.3
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• pp.207-213
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• 2017

In order to investigate the indigenous prokaryotic species diversity of the Nakdong River system in Korea, fresh water samples from Hapcheonho Lake and Jinyangho Lake were analyzed for bacterial taxonomic diversity. The isolated bacterial strains were identified based on 16S rRNA gene sequences, and those exhibiting at least 98.7% sequence similarity with known bacterial species, but never reported in Korea, were selected as unrecorded species. Eleven unrecorded bacterial species were discovered in this study. The isolates were identified as Aquabacterium citratiphilum, Clostridium ghonii, Curvibacter delicates, Deinococcus depolymerans, Eubacterium moniliforme, Flavobacterium nitrogenifigens, Kineosporia mesophila, Luteibacter jiangsuensis, Microbacterium terricola, Rhizobium larrymoorei, and Sediminicoccus rosea belonging to the phyla Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria and Deinococcus-Thermus. The selected isolates were further characterized for cellular and colonial morphologies, growth conditions, physiological properties, and enzymatic activities. Descriptive information of these previously unrecorded species is also provided.

• Journal of Species Research
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• v.7 no.3
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• pp.193-201
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• 2018

Culturable bacterial diversity was investigated using freshwater and sediment samples collected from the North Han River basin in 2017, as a part of the research program 'Survey of freshwater organisms and specimen collection'. Over a thousand bacterial strains were isolated from the samples and identified based on 16S rRNA gene sequences. Among the bacterial isolates, 22 strains showing higher than 98.7% sequence similarity with validly published bacterial species, but not reported in Korea, were classified as unrecorded species in Korea. The 22 bacterial strains were phylogenetically diverse and assigned to 6 classes, 11 orders, 15 families, and 21 different genera. At the generic level, the unreported species were affiliated with Flavobacterium of the class Flavobacteria, Flexibacter of the class Cytophagia, Blastomonas, Brevundimonas, Elstera, Rhizobium, Roseomonas, Sphingomonas, and Xanthobacter of the class Alphaproteobacteria, Albidiferax, Cupriavidus, Curvibacter, Ferribacterium, Hydrogenophaga, Iodobacter, Limnohabitans, Polaromonas, Undibacterium, and Variovorax of the class Betaproteobacteria, Pseudomonas of the class Gammaproteobacteria, and Arcobacter of the class Epsilonproteobacteria. The unreported bacterial species were further characterized by examining Gram reaction, colonial and cellular morphology, and biochemical properties. The detailed descriptions of 22 strains of the unreported bacterial species are also provided.

• Journal of Species Research
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• v.6 no.1
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• pp.15-24
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• 2017

During the extensive survey of the prokaryotic species diversity in Korea, bacterial strains belonging to Betaproteobacteria and Epsilonproteobacteria were isolated from various sources including freshwater, sediment, soil and fish. A total of 23 isolates were obtained, among which 22 strains were assigned to the class Betaproteobacteria and one strain to the class Epsilonproteobacteria. The 22 betaproteobacterial strains were further assigned to Comamonadaceae (11 strains), Burkholderiaceae (6 strains), Oxalobacteraceae (2 strains), Neisseriaceae (1 strain) and unclassified family groups (2 strains). For the strains of Burkholderiaceae, 3 strains were identified as 3 species of Burkholderia, and 2 strains were as 2 species of Cupriavidus. For the strains of Comamonadaceae, 4 strains were identified as 2 species of the genus Hydrogenophaga, 2 strains as 2 species of Acidovorax, 2 strains as 2 species of Limnohabitans, and each of the remaining strains as single species of Comamonas, Curvibacter and Rhodoferax, respectively. For the strains of Oxalobacteraceae, 1 strain was identified as a species of Undibacterium, and the other strain as a species of Herbaspirillum. The strain belonging to Neisseriaceae was identified as a species of Iodobacter. The remaining strains of Betaproteobacteria were identified as species of Sphaerotilus and Methylibium respectively (family unassigned). The epsilonproteobacterial strain was identified as a species of Arcobacter of the family Camplyobacteraceae. The detailed description of each unrecorded species is provided.