Yi-Seul Kim

Analyses of bacterial communities in meju, a Korean traditional fermented soybean bricks, by cultivation-based and pyrosequencing methods

Despite the importance of meju as a raw material used to make Korean soy sauce (ganjang) and soybean paste (doenjang), little is known about the bacterial diversity of Korean meju. In this study, the bacterial communities in meju were examined using both culture-dependent and independent methods in order to evaluate the diversity of the bacterial population. Analyses of the 16S rRNA gene sequences of the bacterial strains isolated from meju samples showed that the dominant species were related to members of the genera Bacillus, Enterococcus, and Pediococcus. The community DNAs extracted from nine different meju samples were analyzed by barcoded pyrosequencing method targeting of the V1 to V3 hypervariable regions of the 16S rRNA gene. In total, 132,374 sequences, with an average read length of 468 bp, were assigned to several phyla, with Firmicutes (93.6%) representing the predominant phylum, followed by Proteobacteria (4.5%) and Bacteroidetes (0.8%). Other phyla accounted for less than 1% of the total bacterial sequences. Most of the Firmicutes were Bacillus and lactic acid bacteria, mainly represented by members of the genera Enterococcus, Lactococcus, and Leuconostoc, whose ratio varied among different samples. In conclusion, this study indicated that the bacterial communities in meju were very diverse and a complex microbial consortium containing various microorganisms got involved in meju fermentation than we expected before.

Deinococcus aerolatus sp. nov. and Deinococcus aerophilus sp. nov., isolated from air samples.

Two strains of pink-coloured bacteria, 5516T-9(T) and 5516T-11(T), were isolated from an air sample collected in Korea. The taxonomic status of these novel strains was investigated by means of a polyphasic approach. The novel strains were Gram-positive, aerobic, non-spore-forming and coccus-shaped bacteria. The DNA G+C contents of strains 5516T-9(T) and 5516T-11(T) were 61.0 and 59.3 mol%, respectively. The major isoprenoid quinone for both strains was MK-8. Strain 5516T-9(T) contained summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c), C(16 : 0) and iso-C(17 : 1)omega9c, and strain 5516T-11(T) contained summed feature 3, iso-C(17 : 1)omega9c, C(17 : 1)omega8c and C(15 : 1)omega6c as the major fatty acids (>10 %). The polar lipid patterns of both strains were similar, comprising one phospholipid and one aminophospholipid as the major components. Phylogenetic analyses using 16S rRNA gene sequences showed that both novel strains were affiliated to the genus Deinococcus. Strain 5516T-9(T) exhibited the highest sequence similarity with Deinococcus marmoris DSM 12784(T) (96.8 %) and strain 5516T-11(T) showed the highest sequence similarity with Deinococcus saxicola DSM 15974(T) (94.5 %). The sequence similarity between strains 5516T-9(T) and 5516T-11(T) was 94.7 %. On the basis of the data presented, it is evident that both strains represent separate novel species of the genus Deinococcus for which the names Deinococcus aerolatus sp. nov. (type strain 5516T-9(T)=KACC 12745(T)=JCM 15442(T)) and Deinococcus aerophilus sp. nov. (type strain 5516T-11(T)=KACC 12746(T)=JCM 15443(T)) are proposed.

Massilia jejuensis sp. nov. and Naxibacter suwonensis sp. nov., isolated from air samples

Two Gram-negative, motile, rod-shaped bacteria (strains 5317J-18T and 5414S-25T) were isolated from air samples collected in the Jeju Island and Suwon region of Korea, respectively. Phylogenetically, strain 5317J-18T was grouped with the genus Massilia with Massilia brevitalea byr23-80T as the closest relative (98.8% sequence similarity). Strain 5414S-25T was affiliated with the genus Naxibacter with Naxibacter haematophilus CCUG 38318T as the closest relative (98.8% sequence similarity). The mean DNA-DNA relatedness values between strain 5317J-18T and M. brevitalea DSM 18925T and Massilia aurea DSM 18055T were 43 and 36%, respectively. The mean DNA-DNA hybridization values between strain 5414S-25T and N. haematophilus KACC 13771T, M. brevitalea DSM 18925T, Massilia timonae DSM 16850T, Naxibacter varians KACC 13770T, M. aurea DSM 18055T, Massilia lutea DSM 17473T and Massilia albidiflava DSM 17472T ranged from 33 to 42%. Both novel strains had ubiquinone Q-8 as the predominant isoprenoid quinone and summed feature 3 (comprising iso-C15:0 2-OH and/or C16:1 omega7c) and C16:0 as the major fatty acids. Both strains also showed similar polar lipid profiles with phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol as the major polar lipids. The DNA G+C contents of strains 5317J-18T and 5414S-25T were 66.1 and 67.8%, respectively. On the basis of their phenotypic, chemotaxonomic and genotypic characteristics, the new strains represent novel species in the genera Massilia and Naxibacter. Strain 5317J-18T (=KACC 12634T=DSM 21309T) is proposed as the type strain of Massilia jejuensis sp. nov. and strain 5414S-25T (=KACC 12635T=DSM 21311T) is proposed as the type strain of Naxibacter suwonensis sp. nov.

Dyella thiooxydans sp. nov., a facultatively chemolithotrophic, thiosulfate-oxidizing bacterium isolated from rhizosphere soil of sunflower (Helianthus annuus L.).

A Gram-negative, aerobic, motile, rod-shaped, thiosulfate-oxidizing bacterium, designated ATSB10(T), was isolated from rhizosphere soil of sunflower (Helianthus annuus L.). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ATSB10(T) was closely related to members of the genera Dyella (96.4-98.1 % 16S rRNA gene sequence similarity) and Luteibacter (96.4-97.0 %) and Fulvimonas soli LMG 19981(T) (96.7 %) and Frateuria aurantia IFO 3245(T) (97.8 %). The predominant fatty acids were iso-C(16 : 0), iso-C(17 : 1)ω9c and iso-C(15 : 0). The major quinone was Q-8. The G+C content of the genomic DNA was 66.0 mol%. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, an unknown phospholipid, unknown aminophospholipids and an unknown aminolipid. On the basis of phenotypic properties, phylogenetic distinctiveness and DNA-DNA relatedness, strain ATSB10(T) represents a novel species in the genus Dyella, for which the name Dyella thiooxydans sp. nov. is proposed. The type strain is ATSB10(T) (=KACC 12756(T) =LMG 24673(T)).

Description of Microvirga aerophila sp. nov. and Microvirga aerilata sp. nov., isolated from air, reclassification of Balneimonas flocculans Takeda et al. 2004 as Microvirga flocculans comb. nov. and emended description of the genus Microvirga.

Two bacterial strains, 5420S-12(T) and 5420S-16(T), isolated from air samples, were characterized using a polyphasic approach. 16S rRNA gene sequence analysis showed that strain 5420S-12(T) was related phylogenetically to Microvirga subterranea FaiI4(T) (97.4 % sequence similarity) and Microvirga guangxiensis 25B(T) (97.1 %) and that strain 5420S-16(T) was closely related to Balneimonas flocculans TFB(T) (98.0 %) and Microvirga guangxiensis 25B(T) (97.2 %). The G+C content of the genomic DNA was 62.2 mol% for strain 5420S-12(T) and 61.5 mol% for strain 5420S-16(T). The major fatty acid was C(18 : 1)ω7c. The results of DNA-DNA hybridization and the phenotypic data showed that strains 5420S-12(T) and 5420S-16(T) could be distinguished from phylogenetically related species and represent two novel species within the genus Microvirga, for which the names Microvirga aerophila sp. nov. (type strain 5420S-12(T) =KACC 12743(T) =NBRC 106136(T)) and Microvirga aerilata sp. nov. (type strain 5420S-16(T) =KACC 12744(T) =NBRC 106137(T)) are proposed. Furthermore, the reclassification of Balneimonas flocculans as Microvirga flocculans comb. nov. (type strain TFB(T) =JCM 11936(T) =KCTC 12101(T) =IAM 15034(T) =ATCC BAA-817(T)) is proposed and an emended description of the genus Microvirga is provided.

Acinetobacter brisouii sp. nov., isolated from a wetland in Korea

A bacterial strain 5YN5-8T was isolated from peat layer on Yongneup in Korea. Cells of strain 5YN5-8T were strictly aerobic, Gram-negative, coccobacilli, non-spore forming, and non-motile. The isolate exhibited optimal growth at 28°C, pH 7.0, and 0–1% NaCl. Results of 16S rRNA gene sequence analyses indicated a close relationship of this isolate to Acinetobacter calcoaceticus (97.8% similarity for strain DSM 30006T). It also exhibited 94.4–97.8% 16S rRNA gene sequence similarities to the validly published Acinetobacter species. The value for DNA-DNA hybridization between strain 5YN5-8T and other members of the genus Acinetobacter ranged from 16 to 28%. Predominant cellular fatty acids were C18:1ω9c, summed feature 4 containing C15:0 iso 2-OH and/or C16:1ω7c, and C16:0. The DNA G+C content was 43.9 mol%. Phylogenetic, phenotypic, and chemotaxonomic data accumulated in this study revealed that the isolate could be classified in a novel species of the genus Acinetobacter. The name Acinetobacter brisouii sp. nov. is proposed for the novel species, with 5YN5-8T (=KACC 11602T = DSM 18516T) as the type strain.

Cohnella yongneupensis sp. nov. and Cohnella ginsengisoli sp. nov., Isolated from Two Different Soils

Two aerobic, Gram-positive, rod-shaped bacterial strains, 5YN10-14(T) and GR21-5(T), were isolated from the Yongneup wetland and ginseng soil in Korea, respectively. The two strains formed ellipsoidal or oval spores positioned centrally or paracentrally in swollen sporangia. On the basis of 16S rRNA gene sequence analysis, these strains were related to members of the genus Cohnella. 16S rRNA gene sequence similarity between strains 5YN10-14(T) and GR21-5(T) was 95.9 %. Strains 5YN10-14(T) and GR21-5(T) showed, respectively, 94.3 and 95.2 % 16S rRNA gene sequence similarity to Cohnella thermotolerans CCUG 47242(T), 94.6 and 94.4 % to Cohnella hongkongensis HKU3(T), 94.7 and 94.7 % to Cohnella laeviribosi RI-39(T), and 95.4 and 94.8 % to Cohnella phaseoli GSPC1(T). The major fatty acids of strain 5YN10-14(T) were anteiso-C(15 : 0) (51.1 %), iso-C(16 : 0) (18.5 %) and C(16 : 0) (13.2 %), and the major fatty acids of strain GR21-5(T) were anteiso-C(15 : 0 ) (48.9 %), iso-C(16 : 0) (15.0 %) and iso-C(15 : 0) (12.2 %). The two strains contained menaquinone with seven isoprene units (MK-7) as the predominant quinone, and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine as major polar lipids; however, strain 5YN10-14(T) also contained lysylphosphatidylglycerol as a major polar lipid, whereas strain GR21-5(T) had an unknown aminophospholipid as another major polar lipid. The DNA G+C contents of strains 5YN10-14(T) and GR21-5(T) were 58.8 and 61.3 mol%, respectively. Based on the results of the phylogenetic and phenotypic data presented, it was concluded that the two strains represent two novel species of the genus Cohnella , for which the names Cohnella yongneupensis sp. nov. (type strain 5YN10-14(T)=KACC 11768(T)=DSM 18998(T)) and Cohnella ginsengisoli sp. nov. (type strain GR21-5(T)=KACC 11771(T)=DSM 18997(T)) are proposed.

Pedobacter rhizosphaerae sp. nov. and Pedobacter soli sp. nov., isolated from rhizosphere soil of Chinese cabbage (Brassica campestris)

Two bacterial strains, 01-96(T) and 15-51(T), isolated from rhizosphere soil of Chinese cabbage (Brassica campestris) were characterized by using a polyphasic approach. 16S rRNA gene sequence analysis showed that strain 01-96(T) was phylogenetically related most closely to Pedobacter suwonensis 15-52(T) and Pedobacter roseus CL-GP80(T) (96.7 and 96.7% similarity, respectively), and strain 15-51(T) to Pedobacter borealis G-1(T) and P. suwonensis 15-52(T) (97.2 and 97.1%, respectively). However, levels of DNA-DNA relatedness between strain 15-51(T) and P. borealis KACC 14287(T) and P. suwonensis KACC 11317(T) were low (<50%). The G+C content of the genomic DNA was 37.8 mol% for strain 01-96(T) and 38.6 mol% for strain 15-51(T). The major fatty acids of the two strains were iso-C(17:0) 3-OH, iso-C(15:0) and summed feature 3 (iso-C(15:0) 2-OH and/or C(16:1)ω7c). The results of DNA-DNA hybridization and phenotypic data showed that strains 01-96(T) and 15-51(T) could be distinguished from their closest phylogenetic relatives, and that these strains represented two novel species of the genus Pedobacter, for which the names Pedobacter rhizosphaerae sp. nov. (type strain 01-96(T) =KACC 14938(T) =NBRC 107690(T)) and Pedobacter soli sp. nov. (type strain 15-51(T) =KACC 14939(T) =NBRC 107691(T)) are proposed.

Leucobacter denitrificans sp. nov., isolated from cow dung

The bacterial strain M1T8B10T was isolated from cow dung in Suwon, Republic of Korea. The strain was a Gram stain-positive rod, nonmotile, and non-spore-forming. According to 16S rRNA gene sequence analysis, the strain fell within the clade of the genus Leucobacter, showing the highest sequence similarities with Leucobacter aridicollis L-9T (98.7%), Leucobacter iarius 40T (98.4%), and Leucobacter komagatae JCM 9414T (98.2%). Cell-wall peptidoglycan contained the diagnostic diamino acid 2,4-diaminobutyric acid of the genus Leucobacter, showing B-type cross-linked peptidoglycans. The major fatty acids were anteiso-C15:0, iso-C16:0, and anteiso-C17:0. The quinone system consisted of the menaquinones MK-11 (78%) and MK-10 (22%). The polar lipid profiles contained diphosphatidylglycerol, phosphatidylglycerol, and an unidentified glycolipid. Differences in several physiological features including nitrate reduction enabled the isolate to be differentiated from all recognized Leucobacter species. Based on these phylogenetic, chemotaxonomic, and phenotypic results, the isolate represents a novel species, for which the name Leucobacter denitrificans sp. nov. is proposed. The type strain is M1T8B10T (=KACC 14055T =NBRC 106309T).

Parapedobacter luteus sp. nov. and Parapedobacter composti sp. nov., isolated from cotton waste compost

Two aerobic, Gram-reaction-negative, non-spore-forming bacterial strains, 4M29T and 4M40T, were isolated from cotton composts. The two strains grew in the presence of 0-5% (w/v) NaCl (optimum growth in the absence of NaCl), at pH 6.0-8.0 (optimum, pH 7.0) and at 15-45 degrees C (optimum, 30 degrees C). The strains shared 97.1% 16S rRNA gene sequence similarity. Strains 4M29T and 4M40T showed the next highest levels of 16S rRNA gene sequence similarity to Parapedobacter koreensis Jip14T (95.6 and 94.4%, respectively) and Parapedobacter soli DCY14T (95.2 and 93.8%). The level of DNA-DNA relatedness between strains 4M29T and 4M40T was 38%. The two strains contained iso-C15:0, summed feature 3 (comprising iso-C15:0 2-OH and/or C16:1omega7c) and iso-C17:0 3-OH as major fatty acids, MK-7 as the major respiratory quinone, homospermidine as the only polyamine and phosphatidylethanolamine as the major polar lipid. The DNA G+C contents of strains 4M29T and 4M40T were 47.6 and 48.6 mol%, respectively. On the basis of phylogenetic and phenotypic data, strains 4M29T and 4M40T are considered to represent two novel species of the genus Parapedobacter, for which the names Parapedobacter luteus sp. nov. (type strain 4M29T =KACC 10955T =JCM 15977T) and Parapedobacter composti sp. nov. (type strain 4M40T =KACC 10972T =JCM 15978T) are proposed.