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Two bacterial strains designated as W3-2-3T and HKS04T were isolated from mineral water and a soil sample, respectively, in the Republic of Korea. The 16S rRNA genes of the two strains shared a sequence similarity of 93.5 %. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains W3-2-3T and HKS04T formed a distinct lineage within the genus Nocardioides of the family Nocardioidaceae (order Propionibacteriales ). The closely related species of strain W3-2-3T were Nocardioides albidus (98.9 %), Nocardioides caeni (98.8 %), Nocardioides kongjuensis (98.6 %), Nocardioides aromaticivorans (98.5 %), Nocardioides nitrophenolicus (98.4 %), Nocardioides flava (98.2 %) and Nocardioides ginsengisoli (98.1 %). The closest species of strain HKS04T was Nocardioides halotolerans (98.7 %). The genome sizes of strains W3-2-3T and HKS04T were 4741198 and 5 120341 bp, respectively. The genomic DNA G+C contents of strains W3-2-3T and HKS04T were 73.3 and 72.1 mol%, respectively. The main fatty acids of strain W3-2-3T were C17:1 ω6c and iso-C16:0 and those of strain HKS04T were iso-C16:0 and iso-C16:0 H. The main polar lipids of both strains were diphosphatidylglycerol and phosphatidylglycerol and the predominant respiratory quinone was MK-8(H4), supporting the affiliation of these strains with the genus Nocardioides . Based on the results of biochemical, chemotaxonomic and phylogenetic analyses, two novel species, Nocardioides convexus W3-2-3T (KACC 21211T=LMG 31251T) and Nocardioides anomalus HKS04T (KACC 18879T=LMG 31249T), are proposed.

Unlike its biosynthetic mechanisms and physiological function, current understanding of riboflavin degradation in soil is limited to a few bacteria that decompose it to lumichrome. Here, we isolated six Microbacterium and three Nocardioides strains. These strains utilized riboflavin and lumichrome, respectively, as carbon sources. Among these strains, we identified Microbacterium paraoxydans R16 (R16) and Nocardioides nitrophenolicus L16 (L16), which were isolated form the same enrichment culture. Co-cultured R16 and L16 reconstituted a riboflavin-degrading interspecies consortium, in which the R16 strain degraded riboflavin to lumichrome and ᴅ-ribose. The L16 strain utilized the lumichrome as a carbon source, indicating that R16 is required for L16 to grow in the consortium. Notably, rates of riboflavin degradation and growth were increased in co-cultured, compared with monocultured R16 cells. These results indicated that a beneficial symbiotic interaction between M. paraoxydans R16 and N. nitrophenolicus L16 results in the ability to degrade riboflavin.

A Gram-stain-positive, aerobic, non-motile, rod-shaped actinobacterium, designated strain 21Sc5-5T, was isolated from a soil sample collected in the Taklamakan desert in Xinjiang Uygur Autonomous Region, PR China and investigated by using a polyphasic approach. Strain 21Sc5-5T grew at 10–37 °C (optimum, 28–30 °C), pH 6.0–9.0 (optimum, pH 7.0) and in the presence of 0–3 % (w/v) NaCl (optimum, 0 %). Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain 21Sc5-5T formed a distinct lineage within the genus Nocardioides and had the highest similarity to Nocardioides albidus THG-S11.7T (97.30 %), followed by Nocardioides kongjuensis A2-4T (97.22 %), Nocardioides nitrophenolicus NSP 41T (97.15 %) and Nocardioides caeni MN8T (97.15 %). The results of chemotaxonomic analyses showed that the isolate possessed ll-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan and MK-8(H4) as the predominant menaquinone. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, an unidentified phospholipid and three unidentified lipids. The major fatty acids were iso-C16 : 0 and 10-methyl C18 : 0. The genome length of strain 21Sc5-5T was 4.67 Mb containing 372 contigs and with a DNA G+C content of 70.4 mol%. On the basis of data from phylogenetic, phenotypic and chemotaxonomic analyses, strain 21Sc5-5T represents a novel species of the genus Nocardioides , for which the name Nocardioides vastitatis sp. nov. is proposed. The type strain is 21Sc5-5T (=JCM 33365T=CGMCC 4.7608T).

A Gram-stain-positive, aerobic, motile, rod- or cocci-shaped bacterium with flagella bacterium (THG-T63T) was isolated from freshwater mud. Growth occurred at 10–40 °C (optimum, 28–35 °C), at pH 6–8 (optimum, 7) and at 0–6 % NaCl (optimum, 2 %). Based on 16S rRNA sequence analysis, the nearest phylogenetic neighbours of strain THG-T63T were identified as Nocardioides panacisoli KCTC 19470T (97.5 %), Nocardioides caeni KCTC 19600T (96.4 %), Nocardioides humi KCTC 19265T (96.3 %), Nocardioides kongjuensis KCTC 19054T (96.1 %) and Nocardioides nitrophenolicus KCTC 457BPT (96.1 %). 16S rRNA sequence similarities among strain THG-T63T and other species were lower than 96.0 %. The polar lipids were phosphatidylglycerol, phosphatidylinositol and one unidentified phospholipid. The quinone system was composed of MK-8 (H4). The major fatty acids were C16 : 0, C17 : 1 ω6c, C17 : 1 ω8c, C18 : 0 10-methyl, C18 : 1 ω9c and iso-C16 : 0. The cell-wall peptidoglycan contained ll-2,6-diaminopimelic acid. The DNA G+C content of strain THG-T63T was 74.6 mol%. Strain THG-T63T exhibited levels of DNA–DNA relatedness of 20–44 % to the type strains of phylogenetically related Nocardioides species and could be differentiated from these species based on differences in phenotypic characteristics. On the basis of the data presented here, strain THG-T63T represents a novel species of the genus Nocardioides , for which the name Nocardioides pelophilus sp. nov. is proposed. The type strain is THG-T63T(=KACC 19192T=CGMCC 4.7388T).

A novel bacterial strain, designated THG-S11.7T, was isolated from garden soil in Incheon, South Korea. Cells of the strain were Gram-stain-positive, aerobic, non-motile cocci, and were catalase- and oxidase-positive. Colonies of the strain were white. Strain THG-S11.7T grew optimally at 28 °C, at pH 7.0 and in the presence of 2.0 % NaCl. 16S rRNA gene sequence analysis indicated that the strain was a member of the genus Nocardioides. Strain THG-S11.7T showed a 16S rRNA gene sequence similarity of 98.2 % to Nocardioides kongjuensis KCTC 19054T, 98.0 % to Nocardioides caeni KCTC 19600T, 97.9 % to Nocardioides daeguensis KCTC 19799T, 97.8 % to Nocardioides nitrophenolicus KCTC 047BPT, 97.6 % to Nocardioides aromaticivorans KACC 20613T, 97.5 % to Nocardioides simplex KACC 20620T and 97.0 % to Nocardioides ginsengisoli KCTC 19135T. DNA-DNA relatedness values between strain THG-S11.7T and the closest phylogenetic neighbours were below 45.0 % and the DNA G+C content of strain THG-S11.7T was 72.2 mol%. Strain THG-S11.7T was characterized chemotaxonomically as having ll-diaminopimelic acid in the cell-wall peptidoglycan and menaquinone MK-8(H4) as the predominant isoprenoid quinone. The major phospholipid was determined to be diphosphatidylglycerol. The major cellular fatty acids of strain THG-S11.7T were iso-C15 : 0, C16 : 0 and iso-C16 : 0. Based on the phenotypic, genotypic and phylogenetic analyses, it is proposed that the isolate represents a novel species of the genus Nocardioides, for which the name Nocardioides albidus sp. nov. is proposed. The type strain is THG-S11.7T ( = KCTC 39607T = CCTCC AB 2015297T).

Using molecular genetic methods, 10 species wereidentified in the community of neutrophilic microorganisms isolated from thebioreactor during the process of biooxidation of gold-arsenicpyrrhotite-bearing sulfide ore flotation concentrate. The microbial communitywas composed of chemolithotrophs oxidizing elemental sulfur and its reducedcompounds and chemoorganotrophs. The predominant S0-oxidizingchemolithotrophic strain and 3 strains of chemoorganotrophs were isolated inpure cultures. Phylogenetic identification of the pure cultures revealed thechemolithotrophic microorganism to belong to Thermithiobacillus tepidarius,while organotrophic microorganisms were identified as Parapedobacter sp.,Nocardioides nitrophenolicus, and Nocardioides sp. Themorphological and physiological characteristics of Thermithiobacillustepidarius and Nocardioides nitrophenolicus, the culturespredominant in the community of neutrophilic microorganisms, were studied.Active growth of T. tepidarius occurs within a temperature range of38–48°C at the optimal pH value of 7.0–7.5. The maximal specific growth rate ofT. tepidarius on sulfur and on solid residue which remains after theprocess of bioleaching/biooxidation of sulfide ore flotation concentrate (biooxidationresidue) was 0.13 and 0.135 h-1, respectively. The average maximalrate of S0 oxidation in the biooxidation residue was 0.107 g S0oxidizedper g S0initial h-1. The ability of Nocardioidesnitrophenolicus to destruct thiocyanate was shown.

A Gram-reaction-positive, rod-shaped, non-spore-forming bacterium (strain 2C1-5T) was isolated from activated sludge of an industrial wastewater treatment plant in Daegu, South Korea. Its taxonomic position was investigated by using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity, the closest phylogenetic relatives were the type strains of Nocardioides nitrophenolicus (98.6 % similarity), N. kongjuensis (98.5 %), N. caeni (98.4 %), N. simplex (98.3 %), N. aromaticivorans (98.1 %) and N. ginsengisoli (97.5 %); the phylogenetic distance from other species with validly published names within the genus Nocardioides was greater than 3 %. Strain 2C1-5T was characterized chemotaxonomically as having ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, MK-8(H4) as the predominant menaquinone and iso-C16 : 0, C16 : 0 and C17 : 1ω6c as the major fatty acids. The G+C content of the genomic DNA was 74.9 mol%. These chemotaxonomic properties and phenotypic characteristics supported the affiliation of strain 2C1-5T to the genus Nocardioides . The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 2C1-5T from existing species with validly published names. Therefore, strain 2C1-5T represents a novel species of the genus Nocardioides , for which the name Nocardioides daeguensis sp. nov. is proposed, with the type strain 2C1-5T ( = JCM 17460T = KCTC 19799T).

17α-Methyltestosterone (MT), a synthetic anabolic androgenic steroid, is widely used in aquafarming for the production of an all male fish population such as Nile tilapia. This study isolated, identified and characterized MT-degrading bacteria in the sediment and water from a masculinizing pond of Nile tilapia fry. Based on the phylogeny, physiological properties and cell morphology, the three isolated MT-degrading bacteria were related closely to Rhodococcus equi , Nocardioides aromaticivorans , and Nocardioides nitrophenolicus . Growth of the three isolated strains was found to be inhibited for MT concentrations in the range of 1.0–10 mg/L. The inhibition of cell growth was found to be modeled using the Haldane's substrate inhibition model. The kinetic constants ranged from 0.13 to 0.19 h −1 for μ max , 0.7–24.8 mg/L for K s and 19.6–76.2 mg/L for K i . Androgenic activity using β-galactosidase assay showed that all strains degraded MT to the products with no androgenic potency.

A Gram-positive, rod- or coccoid-shaped andN-hexanoyl-l-homoserine lactone-degrading bacterial strain, A2-4T, was isolated from a soil in Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain A2-4Tgrew optimally at pH 7.0–8.0 and 30 °C without NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain A2-4Tis most closely related to members of the genusNocardioides. Strain A2-4Tpossessed chemotaxonomic properties indicative of members of the genusNocardioides; the cell-wall peptidoglycan type was based onll-diaminopimelic acid, MK-8(H4) was the predominant menaquinone and iso-C16 : 0was the predominant fatty acid. The DNA G+C content was 72.1 mol%. The 16S rRNA gene sequence of strain A2-4Twas 98.3–99.1 % similar to those of the type strains ofNocardioides simplex,Nocardioides aromaticivoransandNocardioides nitrophenolicusand 93.8–96.3 % similar to those of the type strains of otherNocardioidesspecies. Strain A2-4Tcould be distinguished from the three phylogenetic relatives,N. nitrophenolicus,N. aromaticivoransandN. simplex, by DNA–DNA relatedness (25–42 %) and by differences in some phenotypic characteristics. On the basis of the phenotypic, phylogenetic and genetic data, the strain represents a novel species of the genusNocardioides, for which the nameNocardioides kongjuensissp. nov. is proposed. The type strain is A2-4T(=KCTC 19054T=JCM 12609T).

A p-nitrophenol-degrading bacterial strain was isolated from industrial wastewater. This strain (NSP41T) was identified as a member of the genus Nocardioides from chemotaxonomic characterizations and phylogenetic inference based on 16S rDNA sequence analysis. The G + C content is 71.4 mol%. The diamino acid in the cell-wall peptidoglycan is LL-diaminopimelic acid. The predominant menaquinone is MK-8(H4). The cellular fatty acid profile is similar to those of Nocardioides species. 16S rDNA sequence analysis show that strain NSP41T is the most related to Nocardioides simplex strains with a level of nucleotide similarity of 98.6%. The levels of 16S rDNA similarity between strain NSP41T and other Nocardioides species ranged from 93.8 to 95.1%. This organism is distinguishable from some other Nocardioides species as well as N. simplex strains by DNA-DNA relatedness data. This organism is different from N. simplex strains in some phenotypic characteristics. Therefore, on the basis of the data presented, a new species of the genus Nocardioides, Nocardioides nitrophenolicus, is proposed. The type strain of the new species is strain NSP41T (= KCTC 0457BPT).

A Gram-positive, rod-shaped, non-spore-forming bacterium (Gsoil 346T) was isolated from the soil of a ginseng field in South Korea and was characterized in order to determine its taxonomic position. On the basis of 16S rRNA gene sequences, strain Gsoil 346T was shown to belong to the genus Nocardioides in the family Nocardioidaceae, with the most closely related species being Nocardioides aquiterrae GW-9T (96.6 % 16S rRNA gene sequence similarity); however, the strain clustered in a distinct branch of the phylogenetic tree with Nocardioides kongjuensis A2-4T (96.2 %), Nocardioides aromaticivorans H-1T (96.1 %), Nocardioides nitrophenolicus NSP41T (96.1 %) and Nocardioides simplex ATCC 15799T (95.9 %). Strain Gsoil 346T was characterized chemotaxonomically and found to have ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, phosphatidylinositol and phosphatidylglycerol as the major polar lipids, MK-8(H4) as the predominant menaquinone and iso-C16 : 0, C18 : 1 ω9c and C17 : 1 ω8c as the major fatty acids. The G+C content of the genomic DNA of the novel strain was 73.0 mol%. These chemotaxonomic properties supported the placement of strain Gsoil 346T in the genus Nocardioides. The results of physiological and biochemical tests, along with the phylogenetic analysis, allowed strain Gsoil 346T to be differentiated genotypically and phenotypically from recognized species of the genus Nocardioides. Therefore, strain Gsoil 346T represents a novel species, for which the name Nocardioides panacisoli sp. nov. is proposed, with Gsoil 346T (=KCTC 19470T=DSM 21348T) as the type strain.

A Gram-positive, non-motile, rod- or coccoid-shaped bacterial strain, designated MN8(T), was isolated from sludge of domestic wastewater in Korea, and its taxonomic position was investigated by use of a polyphasic study. Strain MN8(T) grew optimally at pH 6.5-7.5 and 30 degrees C and in the presence of 0-0.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MN8(T) fell within the cluster comprising Nocardioides species, clustering with Nocardioides simplex KCTC 9106(T), Nocardioides aromaticivorans H-1(T), Nocardioides kongjuensis A2-4(T) and Nocardioides nitrophenolicus NSP41(T), with which it shared 98.4-99.0 % 16S rRNA gene sequence similarity. The chemotaxonomic properties of strain MN8(T) were consistent with those of the genus Nocardioides: the cell-wall peptidoglycan type was based on ll-2,6-diaminopimelic acid, the predominant menaquinone was MK-8(H(4)) and the major fatty acids were iso-C(16 : 0) and C(18 : 1)omega9c. The DNA G+C content was 71.5 mol%. Strain MN8(T) exhibited levels of DNA-DNA relatedness of 13-31 % to the type strains of phylogenetically related Nocardioides species and could be differentiated from these species based on differences in phenotypic characteristics. On the basis of the data presented, strain MN8(T) is considered to represent a novel species of the genus Nocardioides, for which the name Nocardioides caeni sp. nov. is proposed. The type strain is MN8(T) (=KCTC 19600(T)=CCUG 57506(T)).

Strain DCY24(T), a Gram-reaction-positive, aerobic, rod-shaped, motile bacterium, was isolated from soil of a ginseng field in South Korea. According to 16S rRNA gene sequence analysis, it was closely related to Nocardioides aromaticivorans DSM 15131(T) (95.1 % similarity), Nocardioides simplex KCTC 9106(T) (95.0 %), Nocardioides nitrophenolicus DSM 15529(T) (94.8 %) and Nocardioides kongjuensis DSM 19082(T) (94.7 %). Chemotaxonomic data revealed that strain DCY24(T) possessed MK-8(H(4)) as the predominant menaquinone, ll-2,6-diaminopimelic acid as the diagnostic diamino acid, phosphatidylglycerol and diphosphatidylglycerol as predominant polar lipids and iso-C(16 : 0), iso-C(17 : 0) and C(18 : 1)omega9c as predominant fatty acids. The DNA G+C content was 71.0 mol%. Based on evidence from this polyphasic study, strain DCY24(T) (=KCTC 19265(T) =LMG 24128(T)) should be classified as the type strain of a novel Nocardioides species, for which the name Nocardioides humi sp. nov. is proposed.

Seven strains of dibenzofuran (DF)-degrading bacteria isolated from dioxin-polluted environments were characterized. These isolates were able to grow with dibenzofuran as the sole carbon and energy source. During the growth with dibenzofuran, they produced a soluble yellow metabolite that exhibited a unique pH-dependent shift of absorption maxima. Dibenzo-p-dioxin and biphenyl were also degraded with pigment production. The isolates were strictly aerobic and chemoorganotrophic and had gram-positive, nonmotile, rod-shaped cells. Chemotaxonomic analyses showed that cells contained L,L-diaminopimeric acid in the peptidoglycan, branched-chain fatty acids as major fatty acids, and menaquinone MK-8(H4) as the sole respiratory quinone. The G + C content of the DNA of the isolates ranged from 72.0 to 72.4 mol%. The 16S rRNA gene sequences of the isolates were very similar to each other (> or = 99.8%). The phylogenetic analysis showed that the isolates formed a cluster with species of the genus Nocardioides with Nocardioides simplex and Nocardioides nitrophenolicus as their nearest neighbors. DNA-DNA hybridization studies showed that the isolates showed a hybridization level of less than 55% to any tested species of the genus Nocardioides. Based on these data, Nocardioides aromaticivorans sp. nov. is proposed for the new DF-degrading isolates. The type strain is strain H-1 (IAM 14992, JCM 11674, DSM 15131).

The properties of 17 strains of a nocardioform actinomycete isolated from soil are described. The hyphae of the primary mycelium of this organism fragment into irregular to rod- to coccus-like elements. The hyphae of the aerial mycelium fragment into rod- to coccus-like elements with smooth surfaces. These elements give rise to new mycelia. The organism is a gram-positive, non-acid-fast, aerobic, mesophile, and it has a cell wall composition of type I (ll-diaminopimelic acid, alanine, glutamic acid, glycine). The deoxyribonucleic acid base composition is 66.5 mol% G+C. The actinomycete is susceptible to phages of a taxon-specific set. Polyvalent Nocardia and Streptomyces phages are not propagated in the nocardioform organism, which is here regarded as belonging to a new genus, Nocardioides, the type species of which is N. albus. The type strain of N. albus is IMET 7807 (Culture Collection of the Zentralinstitut fur Microbiologic und experimentelle Therapie, Jena). It has been deposited in the American Type Culture Collection under the number 27980. The new genus is placed in the family Streptomycetaceae.