Genus Mucilaginibacter Research Articles

Mucilaginibacter Phenanthrenivorans sp. nov., a Novel Phenanthrene Degradation Bacterium Isolated from Wetland Soil

BJC16-A38T, a Gram-negative, aerobic and non-motile rod-shaped strain was isolated from a permafrost wetland soil sample. BJC16-A38T was oxidase- and catalase-positive, and produced pale yellow colonies on modified R2A agar plates. The 16S rRNA gene sequence of BJC16-A38T shared the highest sequence similarity with those of Mucilaginibacter xinganensis BJC16-A31T (97.44%), Mucilaginibacter gotjawali SA3-7T (96.79%) and Mucilaginibacter frigoritolerans FT22T (96.14%). Phylogenetic analysis revealed that BJC16-A38T formed a separate lineage together with strain M. xinganensis BJC16-A31T in the genus Mucilaginibacter. BJC16-A38T contained menaquinone-7 (MK-7) as the predominant isoprenoid quinine. Major fatty acids in cells were iso-C15:0, summed feature 3 (16:1ω7c/16:1ω6c) and iso-C17:03-OH. BJC16-A38T contained phosphatidylethanolamine, two unknown polar lipids, six unidentified phospholipids and an unidentified aminolipid. The Genome of BJC16-A38T was sequenced using the Genome Analyzer IIx sequence platform and 38 contigs were produced in total with an average G + C percentage of 44.00%. The average nucleotide identity (ANI) of BJC16-A38T with respect to those of M. xinganensis BJC16-A31T, M. gotjawali SA3-7T and M. frigoritolerans FT22T were 79.60%, 77.24% and 77.58%, respectively. Digital DNA-DNA hybridization (DDH) values between BJC16-A38T and the tree reference strains were 21.30%, 19.60% and 19.70%, respectively. BJC16-A38T exhibited phenanthrene biodegradation activity that can degrade 88.02% phenanthrene in the MM medium after 7days cultivation. Phenotypic, chemotaxonomic, phylogenetic and genomic characteristics concluded that strain BJC16-A38T represents a novel species of the genus Mucilaginibacter. Hence, the name Mucilaginibacter phenanthrenivorans sp. nov. is proposed. The type strain is BJC16-A38T (= CGMCC 1.12693T = NBRC 110383T).

Mucilaginibacter aquariorum sp. nov., Isolated from Fresh Water.

A Gram-stain-negative, rod-shaped bacterial strain, JC4T, was isolated from a freshwater sample and determined the taxonomic position. Initial identification based on 16S rRNA gene sequences revealed that strain JC4T is affiliated to the genus Mucilaginibacter with a sequence similarity of 97.97% to Mucilaginibacter rigui WPCB133T. The average nucleotide identity and digital DNA-DNA hybridization values between strain JC4T and Mucilaginibacter species were estimated below 80.92% and 23.9%, respectively. Strain JC4T contained summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) and iso-C15:0 as predominant cellular fatty acids. The dominant polar lipids were identified as phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, and two unidentified lipids. The respiratory quinone was MK-7. The genomic DNA G+C content of strain JC4T was determined to be 42.44%. The above polyphasic evidences support that strain JC4T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter aquariorum sp. nov. is proposed. The type strain is JC4T (= KCTC 92230T = LMG 32715T).

Mucilaginibacter rivuli sp. nov., isolated from a water rivulet.

Strain HMF5004T was isolated from a rivulet located in Yongin, Republic of Korea. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain HMF5004T belonged to the genus Mucilaginibacter. Strain HMF5004T was closely related to Mucilaginibacter paludis (97.7%) and Mucilaginibacter gracilis (97.2%). The values of average nucleotide identity and digital DNA-DNA hybridization between strain HMF5004T and M. paludis were 72.8 and 19.2 %, respectively. Cells of strain HMF5004T were Gram-stain-negative, rod-shaped, non-motile, catalase-positive and oxidase-positive. The DNA G+C content of strain HMF5004T was 42.4 mol%. Strain HMF5004T had menaquinone-7 as a major quinone. The major cellular fatty acids included iso-C15 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and anteiso-C15 : 0. The polar lipids of strain HMF5004T contained phosphatidylethanolamine, five unidentified aminolipids, one unidentified aminophospholipid and four unidentified polar lipids. On the basis of the evidence presented in this polyphasic taxonomic study, strain HMF5004T is considered to represent a novel species for which the name Mucilaginibacter rivuli sp. nov. is proposed. The type strain is HMF5004T (=KCTC 82633T=NBRC 115091T).

Production, characterisation, and application of exopolysaccharide extracted from a glacier bacterium Mucilaginibacter sp. ERMR7:07

Mucilaginibacter sp. is known as an exopolysaccharide (EPS) producer. In this study, a potentially novel species of genus Mucilaginibacter was used to extract EPS. Statistical optimisation by Response surface methodology produced 26.4 mg/mL EPS at 20℃, pH 7.4 using 47 mg carbon source/mL. The molecular weight of the extracted EPS was 3045.09 Da as determined by MADI-TOF/TOF-MS. Structural characterisation by monosaccharide composition, methylation, Fourier-transform infrared spectroscopy, and Nuclear magnetic resonance analysis revealed that the EPS was a linear polysaccharide with the sugar backbone of α-D-Glciv(1→4)α-D-Glciii(1→3)β-D-Glcii(1→6)α-D-Glci. The extracted EPS provided 97.91 % viability to mesophilic Escherichia coli under freezing conditions (-80℃) for up to 7 days. Additionally, extracted EPS showed metal ion biosorption ability for Cu2+ (8.36 mg/g), Fe2+ (4.47 mg/g), Mn2+ (0.12 mg/g), and Zn2+ (0.103 mg/g). Owing to these properties, the extracted EPS can be explored for its application as a cryoprotective agent and as a medium to remove toxic metal ions. To the best of our knowledge, this is the first report on the extraction and characterisation of EPS from the genus Mucilaginibacter.

Extrapolymeric substances (EPS) in Mucilaginibacter rubeus P2 displayed efficient metal(loid) bio-adsorption and production was induced by copper and zinc

Strains of the genus Mucilaginibacter, belonging to the phylum Bacteroidetes, have been noted for exhibiting high genome plasticity and for the vigorous production of extracellular polymeric substances (EPS). Here we analyzed the composition and properties of EPS generated by M. rubeus P2, isolated from a gold-copper mine and exhibiting extremely high resistance to multiple heavy metals. Production of EPS increased significantly upon exposure to elevated concentrations of Cu(II) and Zn(II), but not Au(III). In addition, the EPS produced by M. rubeus P2 displayed extremely high bio-adsorption of As(III), Cu(II) and Au(III), but not of Zn(II). Moreover, EPS production in Mucilaginibacter rubeus P2 exposed to 1 mM of Cu(II) was 8.5 times higher than EPS production in the same strain without metal (loid)-exposure. These findings constitute the basis for a future use of these EPS-overproducing bacteria in bioremediation of heavy metal contaminated environments. The functional groups, especially –SH, CO, and N–H/C–N in the fingerprint zone of glutathione (GSH) and polysaccharides-like components of EPS, were the main components of EPS involved in both Zn(II) and Cu(II) binding and removal. Around 31.22% and 5.74% of Cu(II)-treated EPS was shown to exist as (CO) structures and these structures were converted into C–OH and O–C–O upon exposure to Cu(II), respectively. In contrast, (C–OH/C–O–C/P–O–C) groups in EPS were observed to be positively correlated to increasing concentrations of Zn(II) in strain P2. Furthermore, the complete genome of M. rubeus P2 helped us to identify 350 genes involved in carbohydrate metabolism, some of which are predicted to be involved in EPS production and modification. This work describes the first detailed biochemical and biophysical analysis of EPS from any strain of Mucilaginibacter with unique heavy metal binding properties. The results will be useful for a better understanding of how microorganisms such as M. rubeus P2 adapt to heavy metal polluted environments and how this knowledge can potentially be harnessed in biotechnological applications such as industrial waste water purification, bioremediation of heavy metal contaminated soil and beneficial plant microbe interactions. The toolbox provided in this paper will provide a valuable basis for future studies.

Mucilaginibacter segetis sp. nov., Isolated from Soil.

A bacterial strain, SD-gT, was isolated from a soil sample collected on Dokdo Island, South Korea. Cells were observed to be Gram stain negative and short rod shaped, and colonies to be pink in color. Growth of the isolate was observed at 4-30°C, pH 6-8, and in the presence of 0-2.0% NaCl. Analysis of 16S rRNA gene sequences identified strain SD-gT as a member of the genus Mucilaginibacter in the family Sphingobacteriaceae, with high levels of sequence similarity with Mucilaginibacter terrenus ZH6T (96.9%), Mucilaginibacter lutimaris BR-3T (96.8%), Mucilaginibacter carri PR0008KT (96.8%), Mucilaginibacter gilvus F01003T (96.7%), Mucilaginibacter litoreus BR-18T (96.6%), and Mucilaginibacter terrigena 17JY9-4T (96.5%). The genomic DNA G+C content of strain SD-gT was calculated to be 40.6mol%. The predominant respiratory quinone of the isolate was found to be MK-7; the main polar lipid was phosphatidylethanolamine; and the major fatty acids were identified as summed feature 3 (C16:1 ω7c/C16:1 ω6c; 29.0%), C15:0 iso (19.1%), C15:0 iso (28.1%), C16:0 (14.9%), and C17:0 iso 3-OH (7.4%). The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain SD-gT and M. terrenus ZH6T, M. gilvus F01003T, and M. terrigena ranged from 17.7 to 18.4% and 72.1 to 74.0%, respectively. On the basis of its phenotypic properties, genotypic distinctiveness, and chemotaxonomic features, strain SD-gT represents a novel species in the genus Mucilaginibacter, for which the name Mucilaginibacter segetis sp. nov. is proposed. The type strain is SD-gT (= KCTC 82353T = JCM 34284T).

The emergence of beech leaf disease in Ohio: Probing the plant microbiome in search of the cause

AbstractAmerican beech (Fagus grandifolia) is the target of a newly emerging disease in North America called beech leaf disease (BLD) that affects and disfigures leaves and which can lead to tree mortality. Beech leaf disease may be caused by a newly recognized subspecies of the anguinid nematode Litylenchus crenatae subsp. mccannii, but the associations of this nematode with bacterial and fungal taxa are unknown. We examined microbial communities associated with beech leaves affected by BLD in a 16‐year‐old American beech plantation using molecular methods. We detected L. crenatae subsp. mccannii in anywhere from 45% to 90% of leaves depending on the degree of visual BLD symptoms. Approximately 37% of asymptomatic leaves contained L. crenatae subsp. mccannii, whereas 90% of buds associated with symptomatic leaves contained L. crenatae subsp. mccannii. We found that fungal communities on leaves and buds were unaffected by BLD, but bud and leaves had significantly different fungal communities. Bacterial communities on buds also were unaffected by BLD, but bacterial communities were significantly different between symptomatic and asymptomatic leaves suggesting that the nematode could be altering the community of bacteria on the leaves. Clone libraries indicate that Wolbachia, an intracellular endosymbiont of arthropods, was found only on symptomatic leaves and buds associated with either symptomatic or asymptomatic leaves. In addition, only symptomatic leaves contained taxa in the genus Mucilaginibacter, which previous studies suggest could produce exopolysaccharides. These bacterial taxa could represent a marker for the vector of L. crenatae subsp. mccannii that enables spread between trees and a possible endosymbiont that could facilitate nematode feeding and establishment on nematode infested leaves. Our results are the first to examine changes to the leaf microbiome of this newly emerging pest and may aid identification of mechanisms associated with the spread and success of L. crenatae subsp. mccanni.

Mucilaginibacter gilvus sp. nov., isolated from Antarctic soil.

A Gram-stain-negative, aerobic, non-motile, rod-shaped, cold-tolerant bacterium, designated F01003T, was isolated from soil sampled near Happiness Bay on the west coast of Antarctica. Strain F01003T was found to grow at 4-30 °C (optimum, 25 °C), pH 5.5-8.0 (pH 6.5-7.0) and in the presence of 0-1 % NaCl (0 %, w/v). Cells were oxidase-positive and catalase-positive. Strain F01003T contained menaquinone 7 (MK-7) as the predominant respiratory quinone. The main cellular fatty acids included summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and iso-C15 : 0. Phosphatidylethanolamine and an unidentified aminolipid were identified as the major polar lipids. The DNA G+C content of strain F01003T was 44.8 mol%. Phylogenetic analysis of the nearly full-length 16S rRNA gene sequence revealed that strain F01003T was most closely related to the genus Mucilaginibacter and exhibited the highest sequence similarity to Mucilaginibacter phyllosphaerae LMG 29118T (97.3 %). On the basis of the evidence presented in this polyphasic taxonomic study, strain F01003T is considered to represent a novel species of the genus Mucilaginibacter, for which the name Mucilaginibactergilvus sp. nov. is proposed. The type strain is F01003T (=KCTC 62991T=CCTCC AB 2019023T).

Mucilaginibacter corticis sp. nov., isolated from bark of Pinus koraiensis.

A gram-stain negative, aerobic, non-motile and rod-shaped novel bacterial strain, designated MAH-19T, was isolated from bark of Pinus koraiensis. The colonies were observed to be light pink coloured, smooth, circular and 0.3-0.7mm in diameter when grown on R2A agar for 2days. Strain MAH-19T was found to be able to grow at 10-35°C (optimum 28-30°C), at pH 6.0-8.0 (optimum 7.0) and at 0-0.5% NaCl (optimum 0%). Cell growth occurs on nutrient agar and R2A agar. The strain was found to be positive for both catalase and oxidase tests. Cells are able to hydrolyse aesculin and Tween 20, but not casein, gelatin, starch, L-tyrosine, DNA, L-arginine, urea or Tween 80. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Mucilaginibacter and to be closely related to Mucilaginibacter panaciglaebae BXN5-31T (97.4% similarity), Mucilaginibacter antarcticus S14-88T (97.2%) and Mucilaginibacter ximonensis XM-003T (97.1%). In DNA-DNA hybridization tests, the DNA relatedness between strain MAH-19T and its close phylogenetic neighbours was below 45.0%. The novel strain MAH-19T has a draft genome size of 5,335,442bp (14 contigs), annotated with 4963 protein-coding genes, 44 tRNA and 6 rRNA genes. The genomic DNA G+C content was determined to be 42.7mol%. The predominant isoprenoid quinone of strain MAH-19T was identified as MK-7. The major fatty acids were identified as C15:0 iso and summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c). The DNA-DNA hybridization results and results of the genotypic analysis, in combination with chemotaxonomic and physiological data, demonstrated that strain MAH-19T represents a novel species within the genus Mucilaginibacter, for which the name Mucilaginibacter corticis sp. nov. is proposed, with MAH-19T (= KACC 19745T = CGMCC1.13657T) as the type strain.

Mucilaginibacter terrenus sp. nov., isolated from manganese mine soil.

Strain ZH6T is a Gram-stain-negative, rod-shaped, aerobic bacterium isolated from manganese mine soil. Strain ZH6T had highest 16S rRNA gene sequence similarities to Mucilaginibacter yixingensis YX-36T (96.9 %) and Mucilaginibacter psychrotolerans NH7-4T (96.8 %). The genome size of strain ZH6T was 4.61 Mb with a DNA G+C content of 44.0 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain ZH6T and M. yixingensis DSM 26809T were 70.6 and 19.2 %, respectively. Strain ZH6T had menaquinone-7 as a major quinone and main cellular fatty acids of iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The polar lipids of strain ZH6T were a phosphatidylethanolamine, an unidentified glycolipid, an unidentified phospholipid, three unidentified aminophospholipids and four unidentified lipids. Based on the phenotypic, chemotaxonomic and phylogenetic results, strain ZH6T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacterterrenus sp. nov., is proposed. The type strain is ZH6T (=CCTCC AB 2018373T=KCTC 72075T).

Mucilaginibacter hurinus sp. nov., isolated from briquette warehouse soil.

A novel bacterial strain, designated ZR32T, was isolated from briquette warehouse soil in Ulsan (Korea). The strain was aerobic, showing pink-colored colonies on R2A agar. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain ZR32T was closely related to Mucilaginibacter soli R9-65T (97.0%), Mucilaginibacter gynuensis YC7003T (96.9%), and Mucilaginibacter lutimaris BR-3T (96.8%). The values of DNA-DNA relatedness related two highest strains M. soli R9-65T and M. gynuensis YC7003T were 31.2 ± 6.9% and 19.7 ± 0.3%, respectively. Its genome size was 3.9Mb, comprising 3402 predicted genes. The DNA G+C content of strain ZR32T was 43.0mol%. The major cellular fatty acids (>5% of total) were summed feature 3 (C16:1ω6c and/or C16:1ω7c), C16:0, C16:1ω5c, iso-C15:0, iso-C17:0 3-OH, and C17:1ω9c. The major respiratory quinine was menaquinone-7 (MK-7). The major polar lipids were phosphatidylethanolamine, two unidentified phospholipids, one unidentified sphingolipid, and one unidentified polar lipid. Strain ZR32T showed distinctive characteristics such as the temperature and pH for growth ranges, being positive for β-glucosidase, salicin production, negative for N-acetyl-glucosamine assimilation, being resistant to carbenicillin and piperacillin to related species. On the basis of phenotypic, chemotaxonomic, and phylogenetic data, strain ZR32T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter hurinus sp. nov. is proposed. The type strain is ZR32T (= KCTC 62193 = CCTCC AB 2017285).

Mucilaginibacter limnophilus sp. nov., isolated from a lake.

A polyphasic taxonomy approach was used to characterize strain YBJ-36T, isolated from a freshwater lake in Taiwan. Phylogenetic analyses, based on 16S rRNA gene sequences and coding sequences of an up-to-date bacterial core gene set (92 protein clusters), indicated that strain YBJ-36T formed a phylogenetic lineage in the genus Mucilaginibacter. 16S rRNA gene sequence similarity indicated that strain YBJ-36T is closely related to species within the genus Mucilaginibacter (93.8-97.8% sequence similarity) and is most similar to Mucilaginibacter fluminis TTM-2T (97.8%), followed by Mucilaginibacter roseus TTM-1T (97.2%). Microbiological analyses demonstrated that strain YBJ-36T is Gram-negative, aerobic, non-motile, rod-shaped, surrounded by a thick capsule, and forms pink-colored colonies. Strain YBJ-36T grew between 20-40°C (optimal range, 35-37°C), pH 5.5-7.0 (optimal pH of 6) and 0-2% NaCl (optimal concentration, 0.5%). The predominant fatty acids of strain YBJ-36T are iso-C15:0 and summed feature 3 (C16:1ω7c and/or C16:1ω6c), the major polar lipid is phosphatidylethanolamine, the major polyamine is homospermidine, and the major isoprenoid quinone is MK-7. The draft genome is approximately 4.63 Mb in size with a G+C content of 42.8 mol%. Strain YBJ-36T exhibited less than 35% DNA-DNA relatedness with Mucilaginibacter fluminis TTM-2T and Mucilaginibacter roseus TTM-1T. Based on phenotypic and genotypic properties and phylogenetic inference, strain YBJ-36T should be classified in a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter limnophilus sp. nov. is proposed. The type strain is YBJ-36T (= BCRC 81056T = KCTC 52811T = LMG 30058T).

Mucilaginibacter terrigena sp. nov. sp., A Novel Member of the Family Sphingobacteriaceae.

A bacterial strain, 17JY9-4T, was isolated from a soil sample collected on Jeju Island, South Korea. Colonies grown on R2A agar are pale pink in color, and cells are Gram-stain negative, short, and rod-shaped. Analysis of 16S rRNA gene sequences identified this strain as a member of the genus Mucilaginibacter in the family Sphingobacteriaceae, with high levels of 16S rRNA sequence similarity shared with Mucilaginibacter lutimaris BR-3T (98.0%), Mucilaginibacter rigui WPCB133T (98.0%), Mucilaginibacter phyllosphaerae PP-F2F-G21T (97.0%), Mucilaginibacter amnicola TAPP7T (96.8%), and Mucilaginibacter soli R9-65T (96.7%). Growth of strain 17JY9-4T occurs at 10-30°C, pH 6-8, and in the presence of 0-1.0% NaCl. The genomic G+C content is 44.38mol%. The predominant respiratory quinone of the isolate is MK-7; the major fatty acids are summed feature 3 (C16:1ω7c/C16:1ω6c) (39.7%), iso-C15:0 (22.8%), iso-C17:0 3-OH (7.8%), and C16:0 (7.7%); and the major polar lipid is phosphatidylethanolamine. The phenotypic and chemotaxonomic data support the placement of strain 17JY9-4T within the genus Mucilaginibacter. However, the DNA-DNA relatedness between the isolate and M. rigui, M. lutimaris, M. phyllosphaerae, M. amnicola, and M. soli were 44.3 ± 3.0%, 38.6 ± 3.7%, 23.2 ± 2.9%, 21.9 ± 3.1%, and 18.6 ± 3.7%, respectively. The results of 16S rRNA gene sequence similarity analysis, DNA-DNA hybridization analysis, and the observed differentiating phenotypic properties from other closely related taxa clearly indicate that strain 17JY9-4T represents a novel species in the genus Mucilaginibacter, for which the name Mucilaginibacter terrigena sp. nov. is proposed. The type strain is 17JY9-4T (= KCTC 62294T = JCM 33049T).

Mucilaginibacter aquatilis sp. nov., Mucilaginibacter arboris sp. nov., and Mucilaginibacter ginkgonis sp. nov., novel bacteria isolated from freshwater and tree bark.

Three Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strains, designated as HME9299T, HMF7410T and HMF7856T, were isolated from freshwater and tree bark collected in Yong-in, Republic of Korea. Strains HME9299T, HMF7410T and HMF7856T exhibited the highest 16S rRNA gene sequence similarities of 97.2, 94.4 and 96.4 % to Mucilaginibacter daejeonensis Jip 10T, Mucilaginibacter terrae CCM 8645T and Mucilaginibacter phyllosphaerae PP-F2F-G21T, respectively. Among themselves, the values were 94.1-95.7 %. Phylogenetic analysis of the 16S rRNA gene sequences of the three isolates revealed that they belonged to the genus Mucilaginibacter within the family Sphingobacteriaceae. The predominant fatty acids of three strains were summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c) and iso-C15 : 0. Strain HME9299T contained a relatively large amount of C16 : 1 ω5c. The predominant respiratory quinone was menaquinone-7. The genome sizes of strains HME9299T, HMF7410T and HMF7856T were 4.33, 4.16 and 3.68 Mbp, respectively, and their DNA G+C contents were 41.6, 38.4 and 43.9 mol%, respectively. Based on the results of the phenotypic, genotypic, chemotaxonomic and phylogenetic investigation, three novel species, Mucilaginibacter aquatilis sp. nov, Mucilaginibacter arboris sp. nov. and Mucilaginibacter ginkgonis sp. nov., are proposed. The type strains are HME9299T (=KCTC 42122T=DSM 29146T), HMF7410T (=KCTC 62464T=NBRC 113227T) and HMF7856T (=KCTC 72782T=NBRC 114275T), respectively.

Mucilaginibacter inviolabilis sp. nov., isolated from the phycosphere of Haematococcus lacustris NIES 144 culture.

A Gram-stain-negative, non-motile, rod-shaped, aerobic bacterial strain, designated HC2T, was isolated from the phycosphere of Haematococcus lacustris NIES 144 culture. Strain HC2T was able to grow at pH 4.5-8.0, at 4-32 °C and in the presence of 0-2 % (w/v) NaCl. Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain HC2T was affiliated to the genus Mucilaginibacter and shared the highest sequence similarity with Mucilaginibacter lappiensis ANJKI2T (98.20 %) and Mucilaginibacter sabulilitoris SMS-12T (98.06 %). Strain HC2T contained summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and iso-C15 : 0 as the major fatty acids (>10.0 %). The major polar lipids were phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, two unidentified aminolipids and four unidentified lipids. The respiratory quinone was menaquinone 7 (MK-7). The genomic DNA G+C content was 42.0 %. On the basis of the phenotypic, chemotaxonomic and phylogenetic characteristics, strain HC2T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter inviolabilis sp. nov. is proposed. The type strain is HC2T (=KCTC 82084T=JCM 34116T).

Mucilaginibacter endophyticus sp. nov., an endophytic polysaccharide-producing bacterium isolated from a stem of Miscanthus sinensis.

In this study, a Gram-negative, rod-shaped, endophytic bacterial strain (RS1T) capable of producing large amounts of exopolysaccharides was isolated from a stem of Miscanthus sinensis. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain RS1T is closely related to Mucilaginibacter kameinonensis NBRC 102645T (98.72%), followed by Mucilaginibacter gossypiicola Gh-48T (97.56%) and Mucilaginibacter oryzae DSM 19975T (97.36%). The DNA G + C content of strain RS1T was determined to be 42.80mol%. ANIb and GGDC values from genomic comparison between the genomes of strain RS1T and the related reference species were less than 95% and 70%, respectively. The major cellular fatty acids (more than 10% of total fatty acids) were identified as iso-C15: 0, C16:0, iso-C17:0-3OH and summed feature 3 (C16: 1ω7c and/or iso-C15:02-OH). The only isoprenoid quinone detected was MK-7. Based on the physiological, genotypic and genomic characteristics, strain RS1T is concluded to represent a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter endophyticus sp. nov. is proposed (type strain RS1T = KCTC 62785T = GDMCC 1.1414T).

Mucilaginibacter xinganensis sp. nov., a phenanthrene-degrading bacterium isolated from wetland soil.

An aerobic, Gram-stain negative, rod-shaped and non-motile strain, BJC16-A31T, was isolated from the wetland soil sample taken from Daxing'anling, Heilongjiang, People's Republic of China. Strain BJC16-A31T was found to be oxidase- and catalase-positive, and produced light orange colonies on modified R2A agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain BJC16-A31T is closely related to Mucilaginibacter gotjawali SA3-7T with 96.54% sequence similarity and it formed a separate lineage in the genus Mucilaginibacter. Strain BJC16-A31T contained menaquinone-7 (MK-7) as the predominant isoprenoid quinine. Anteiso-C15:0, C16:0 and anteiso-C15:0 were the major fatty acids. The major polar lipids were phosphatidylethanolamine, six unidentified polar lipid, two unidentified aminophospholipids and one unidentified aminolipid. The genome is composed of a circular 5,301,339bp chromosome with average G + C percentage of 42.25%. The Average Nucleotide Identity (ANI) between strain BJC16-A31T and M. gotjawali SA3-7T was 77.51%. Combined phenotypic, chemotaxonomic, phylogenetic and genomic characteristics support the conclusion that strain BJC16-A31T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter xinganensis sp. nov. is proposed. The type strain is BJC16-A31T (= CGMCC 1.12728T = NBRC 110384T).

Mucilaginibacter formosus sp. nov., a bacterium isolated from road-side soil.

A Gram-stain negative, aerobic, non-motile and rod-shaped novel bacterial strain, designated as MAH-5T, was isolated from a road-side soil sample and was characterised by using a polyphasic taxonomic approach. The colonies were observed to be yellowish orange in colour, smooth, circular and 0.3-0.7mm in diameter when grown on nutrient agar for 2days. Strain MAH-5T was found to be able to grow at 15-35°C and at pH 4.0-8.0. The strain was observed to be positive for both the catalase and oxidase tests. Cells were found to be able to hydrolyse aesculin, gelatin and starch. By 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Mucilaginibacter and to be closely related to Mucilaginibacter panaciglaebae BXN5-31T (98.35%), Mucilaginibacter soyangensis HME6664T (97.82%), Mucilaginibacter antarcticus S14-88T (97.49%) and Mucilaginibacter ximonensis XM-003T (97.06%). In DNA-DNA hybridization tests, the DNA relatedness values between strain MAH-5T and its close phylogenetic neighbors were below 45.0%. The genomic DNA G + C content of strain MAH-5T was determined to be 41.5mol% and the predominant isoprenoid quinine was identified as MK-7. The major fatty acids were identified as C15:0 iso and summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c). The genetic characteristics, in combination with chemotaxonomic and physiological data, demonstrated that the isolated strain MAH-5T represents a novel species within the genus Mucilaginibacter, for which the name Mucilaginibacter formosus sp. nov. is proposed, with MAH-5T as the type strain (= KACC 19291T = CGMCC1.16489T).

Mucilaginibacter amnicola sp. nov., isolated from a freshwater creek.

A pink-coloured bacterial strain, TAPP7T, was isolated from a freshwater creek in Taiwan. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain TAPP7T belonged to the genus Mucilaginibacter and showed highest similarity with Mucilaginibacter ginsengisoli B4Y-8T (97.6 %) and Mucilaginibacter carri PR0008KT (96.9 %). Cells of strain TAPP7T were Gram-staining-negative, aerobic, poly-β-hydroxybutyrate-accumulating and short-rod-shaped. Growth occurred at 10-30 °C (optimum, 15-20 °C), at pH 4-8 (optimum, pH 6) and with 0-1 % NaCl (optimum, 0.5 %). The predominant fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and iso-C15 : 0. The polar lipid profile consisted of phosphatidylethanolamine and several uncharacterized aminophospholipids and phospholipids. The major polyamine was homospermidine. The major isoprenoid quinone was MK-7. The DNA G+C content of the genomic DNA was 45.6 mol%. The DNA-DNA relatedness of strain TAPP7T with respect to Mucilaginibacter ginsengisoli B4Y-8T was less than 35 %. On the basis of the phylogenetic inference and phenotypic data, strain TAPP7T should be classified as a novel species, for which the name Mucilaginibacter amnicola sp. nov. is proposed. The type strain is TAPP7T (=BCRC 80976T=LMG 29556T=KCTC 52238T).

Mucilaginibacter panaciglaebae sp. nov., isolated from soil of a ginseng field.

A Gram-reaction-negative, strictly aerobic, non-motile and rod-shaped bacterium, designated strain BXN5-31T, was isolated from soil of a ginseng field, and its taxonomic position was investigated using a polyphasic approach. Strain BXN5-31T grew at 18-37 °C and at pH 6.0-8.0 on R2A medium. Based on 16S rRNA gene sequence similarity, strain BXN5-31T was shown to belong to the genus Mucilaginibacter and was closely related to Mucilaginibactersoyangensis HME6664T, Mucilaginibacterximonensis XM-003T and Mucilaginibacterpuniceus WS71T. The DNA G+C content was 43.6 %. The predominant respiratory quinone was menaquinone 7 (MK-7) and the major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c). The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The DNA-DNA hybridization values between strain BXN5-31T and three reference strains (M. soyangensis HME6664T, M. ximonensis XM-003T and M. puniceus WS71T) were 9.4±1.9, 8.2±1.3 and 5.7±0.7 %, respectively. The DNA G+C content and chemotaxonomic data supported the affiliation of strain BXN5-31T to the genus Mucilaginibacter. Moreover, the physiological and biochemical results and low level of DNA-DNA relatedness allowed the phenotypic and genotypic differentiation of strain BXN5-31T from recognized species of the genus Mucilaginibacter. The isolate therefore represents a novel species, for which the name Mucilaginibacter panaciglaebae sp. nov. is proposed. The type strain is BXN5-31T (=KACC 14957T=JCM 17085T).