Rhodoferax lithotrophicus sp. nov., a neutrophilic iron-oxidizing and -reducing bacterium isolated from iron-rich freshwater sediments.

A neutrophilic iron-oxidizing and -reducing bacterium, strain MIZ03T, was previously isolated from a wetland in Ibaraki, Japan. Here, we report the detailed characteristics of this strain. It was motile with a single polar flagellum, and Gram-stain-negative. It could grow not only chemolithoautotrophically but also chemoorganotrophically by aerobic respiration and fermentation. Major cellular fatty acids were C16 : 1 ω7c/C16 : 1 ω6c, and C16 : 0. Phylogenetic analyses indicated that strain MIZ03T belonged to the genus Rhodoferax. This strain was closely related to Rhodoferax ferrireducens with 98.5 % of 16S rRNA gene sequence similarity. Based on its phenotypic and genomic based characteristics, we conclude that strain MIZ03T represents a new species in the genus Rhodoferax. We propose the name Rhodoferax lithotrophicus sp. nov. to accommodate this strain. The type strain is MIZ03T (=JCM 34246T=DSM 113266T). We also propose the name Rhodoferax koreensis sp. nov., of which the type strain is DCY110T (=KCTC 52288T=JCM 31441T), for the effectively, but not yet validly, published name 'Rhodoferax koreense'.

Iron corrosion concomitant with nitrate reduction by Iodidimonas nitroreducens sp. nov. isolated from iodide-rich brine associated with natural gas.

Microbially influenced corrosion (MIC) may contribute significantly to corrosion-related failures in injection wells and iron pipes of iodine production facilities. In this study, the iron (Fe0) corroding activity of strain Q-1 isolated from iodide-rich brine in Japan and two Iodidimonas strains phylogenetically related to strain Q-1 were investigated under various culture conditions. Under aerobic conditions, the Fe0 foil in the culture of strain Q-1 was oxidized in the presence of nitrate and yeast extract, while those of two Iodidimonas strains were not. The amount of oxidized iron in this culture was six times higher than in the aseptic control. Oxidation of Fe0 in aerobic cultures of nitrate-reducing bacterium Q-1 was dependent on the formation of nitrite from nitrate. This Fe0 corrosion by nitrate-reducing bacterium Q-1 started after initial nitrite accumulation by day 4. Nitrate reduction in strain Q-1 is a unique feature that distinguishes it from two known species of Iodidimonas. Nitrite accumulation was supported by the encoding of genes for nitrate reductase and the missing of genes for nitrite reduction to ammonia or nitrogen gas in its genome sequence. Phylogenetic position of strain Q-1 based on the 16S rRNA gene sequence was with less than 96.1% sequence similarity to two known Iodidimonas species, and digital DNA-DNA hybridization (dDDH) values of 17.2-19.3%, and average nucleotide identity (ANI) values of 73.4-73.7% distinguished strain Q-1 from two known species. In addition of nitrate reduction, the ability to hydrolyze aesculin and gelatin hydrolysis and cellular fatty acid profiles also distinguished strain Q-1 from two known species. Consequently, a new species, named Iodidimonas nitroreducens sp. nov., is proposed for the nitrate-reducing bacterium strain Q-1T.

Corrigendum: Iron corrosion concomitant with nitrate reduction by Iodidimonas nitroreducens sp. nov. isolated from iodide-rich brine associated with natural gas.

[This corrects the article DOI: 10.3389/fmicb.2023.1232866.].

Sideroxyarcus emersonii gen. nov. sp. nov., a neutrophilic, microaerobic iron- and thiosulfate-oxidizing bacterium isolated from iron-rich wetland sediment.

A neutrophilic iron-oxidizing bacterium, strain MIZ01T, which was previously isolated from a wetland in Ibaraki, Japan, was taxonomically characterized in detail. Strain MIZ01T was a motile, curved-rod shaped, Gram-stain-negative bacterium. It was able to grow at 10-40 °C (optimally at 30-35 °C) and at pH 5.5-7.0 (optimally at pH 6.0). It grew microaerobically and chemolithoautotrophically using thiosulfate, in addition to ferrous iron, as the sole electron donor. Major cellular fatty acids of strain MIZ01T were C16 : 1 ω7c/C16 : 1 ω6c and C16 : 0. The complete genome sequence (2.74 Mbp) was determined, showing that its DNA G+C content was 60.0 mol%. Phylogenetic analyses indicated that strain MIZ01T belonged to the family Gallionellaceae, class Betaproteobacteria, and was closely related to an isolate tentatively named 'Sideroxydans lithotrophicus' ES-1 (98.2 % of 16S rRNA gene sequence similarity). Based on its phenotypic and phylogenetic characteristics, we conclude that strain MIZ01T represents a new genus and species in the family Gallionellaceae for which we propose the name Sideroxyarcus emersonii gen. nov., sp. nov. The type strain is strain MIZ01T (=JCM 39089T=DSM 111897T).

Nitrite as a causal factor for nitrate-dependent anaerobic corrosion of metallic iron induced by Prolixibacter strains.

Microbially influenced corrosion (MIC) may contribute significantly to overall corrosion risks, especially in the gas and petroleum industries. In this study, we isolated four Prolixibacter strains, which belong to the phylum Bacteroidetes, and examined their nitrate respiration- and Fe0 -corroding activities, together with two previously isolated Prolixibacter strains. Four of the six Prolixibacter strains reduced nitrate under anaerobic conditions, while the other two strains did not. The anaerobic growth of the four nitrate-reducing strains was enhanced by nitrate, which was not observed in the two strains unable to reduce nitrate. When the nitrate-reducing strains were grown anaerobically in the presence of Fe0 or carbon steel, the corrosion of the materials was enhanced by more than 20-fold compared to that in aseptic controls. This enhancement was not observed in cultures of the strains unable to reduce nitrate. The oxidation of Fe0 in the anaerobic cultures of nitrate-reducing strains occurred concomitantly with the formation of nitrite. Since nitrite chemically oxidized Fe0 under anaerobic and aseptic conditions, the corrosion of Fe0 - and carbon steel by the nitrate-reducing Prolixibacter strains was deduced to be mainly enhanced via the biological reduction of nitrate to nitrite, followed by the chemical oxidation of Fe0 to Fe2+ and Fe3+ coupled to the reduction of nitrite.

An extracellular [NiFe] hydrogenase mediating iron corrosion is encoded in a genetically unstable genomic island in Methanococcus maripaludis.

Certain methanogens deteriorate steel surfaces through a process called microbiologically influenced corrosion (MIC). However, the mechanisms of MIC, whereby methanogens oxidize zerovalent iron (Fe0), are largely unknown. In this study, Fe0-corroding Methanococcus maripaludis strain OS7 and its derivative (strain OS7mut1) defective in Fe0-corroding activity were isolated. Genomic analysis of these strains demonstrated that the strain OS7mut1 contained a 12-kb chromosomal deletion. The deleted region, termed "MIC island", encoded the genes for the large and small subunits of a [NiFe] hydrogenase, the TatA/TatC genes necessary for the secretion of the [NiFe] hydrogenase, and a gene for the hydrogenase maturation protease. Thus, the [NiFe] hydrogenase may be secreted outside the cytoplasmic membrane, where the [NiFe] hydrogenase can make direct contact with Fe0, and oxidize it, generating hydrogen gas: Fe0 + 2 H+ → Fe2+ + H2. Comparative analysis of extracellular and intracellular proteomes of strain OS7 supported this hypothesis. The identification of the MIC genes enables the development of molecular tools to monitor epidemiology, and to perform surveillance and risk assessment of MIC-inducing M. maripaludis.

Faecalimonas umbilicata gen. nov., sp. nov., isolated from human faeces, and reclassification of Eubacterium contortum, Eubacterium fissicatena and Clostridium oroticum as Faecalicatena contorta gen. nov., comb. nov., Faecalicatena fissicatena comb. nov. and Faecalicatena orotica comb. nov.

Two bacterial strains, designated EGH7T and TSAH33, were isolated from human faeces and characterized by using a polyphasic taxonomic approach that included analysis of morphology, phenotypic and biochemical features, cellular fatty acid profiles and phylogenetic position based on 16S rRNA and hsp60 gene sequence analyses. The results of 16S rRNA gene sequence analysis indicated that these strains represented members of the family Lachnospiraceae and formed a monophyletic cluster near Eubacterium contortum JCM 6483T (95 % sequence similarity), Ruminococcus gnavus JCM 6515T (95 %), Clostridium oroticum JCM 1429T (95 %), Eubacterium fissicatena JCM 31501T (95 %) and Clostridium nexile JCM 31500T (94 %). The results of a hsp60 gene sequence analysis supported the phylogenetic tree based on the 16S rRNA gene sequence, with a sequence similarity value of between 77.9 and 84.8 % to the five strains listed above. The novel strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-stain-positive cocco-bacilli. The strains formed characteristic umbilicated colonies on EG agar plates. The major cellular fatty acids were C18 : 1ω9c, C16 : 0 and C18 : 1ω9c dimethyl acetal (DMA). EGH7T and TSAH33 have DNA G+C contents of 46.9 and 45.5 mol%, respectively. On the basis of these data, strains EGH7T and TSAH33 represent a novel species of a novel genus, for which the name Faecalimonas umbilicata gen. nov., sp. nov. is proposed. The type strain of F. umbilicata is EGH7T (=JCM 30896T=DSM 103426T).

Iodidimonas muriae gen. nov., sp. nov., an aerobic iodide-oxidizing bacterium isolated from brine of a natural gas and iodine recovery facility, and proposals of Iodidimonadaceae fam. nov., Iodidimonadales ord. nov., Emcibacteraceae fam. nov. and Emcibacterales ord. nov.

A chemo-organotrophic iodide (I-)-oxidizing bacterial strain, C-3T, isolated from natural gas brine of an iodine recovery facility in Kujukuri, Chiba, Japan, was characterized for representation of a novel species in the class Alphaproteobacteria. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the nearest neighbours of strain C-3T were members of the genera Eilatimonas, Kordiimonas, Rhodothalassium and Temperatibacter with 88-91 % sequence similarity. Cells of strain C-3T were aerobic, Gram-staining-negative, non-sporulating and rod-shaped (1.3-3.6 µm in length). Strain C-3T grew optimally at 30 °C, pH 7.5 and with 3 % NaCl (w/v). Iodide oxidation to form molecular iodine (I2) was a unique trait for strain C-3T, whereas the strain did not utilize iodide as a sole electron donor for chemolithoautotrophic growth. The major isoprenoid quinone was Q-10. The major cellular fatty acids were C18 : 1ω7c and C16 : 1ω5c. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and unidentified aminolipids. The G+C content of the genomic DNA was 58.5 mol%. Iodide oxidation and the major cellular fatty acids composition distinguished strain C-3T from phylogenetically related bacteria. On the basis of the phenotypic features and the phylogenetic position, a novel genus and species are proposed for strain C-3T (=JCM 17843T=LMG 28660T), to be named Iodidimonas muriae gen. nov., sp. nov. We also propose to place the distinct sublineages of the genera Iodidimonasgen. nov. and Emcibacter in the orders Iodidimonadales ord. nov. and Emcibacterales ord. nov., respectively, because these genera are located far apart from the order Kordiimonadales and form the distinct lineage in the class Alphaproteobacteria.

Athalassotoga saccharophila gen. nov., sp. nov., isolated from an acidic terrestrial hot spring, and proposal of Mesoaciditogales ord. nov. and Mesoaciditogaceae fam. nov. in the phylum Thermotogae.

A novel moderately thermophilic, weakly acidophilic, heterotrophic, anaerobic, short-rod bacterium having an outer sheath-like structure (toga) was isolated from a low-salt acidic terrestrial hot spring in Oku-Shiobara, Tochigi, Japan. The strain, designated NAS-01T, grew between 30 and 60 °C (optimum 55 °C), and at pH 4.5 and 7.5 (optimum pH 5.5 to 6.0) and could not grow in media with ≥ 1 % NaCl (optimum 0 % NaCl). It utilized Fe(III), thiosulfate or l-cystine as electron acceptor for growth, and yeast extract, peptone or a variety of sugars as carbon and energy sources. The major cellular fatty acid was C16 : 0, and no lipoquinone was detected. Strain NAS-01T contained phospholipids and glycolipids, but not aminolipids. The DNA G+C content was 41.1 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the strain was included in the phylum Thermotogae, and was closely related to Mesoaciditoga lauensis. The 16S rRNA gene sequence similarity between them was 90 %, and they were deeply branched off the rest of the known Thermotogae species. On the basis of the phylogenetic and ecophysiological properties, strain NAS-01T represents a novel species of a new genus in the phylum Thermotogae, for which we propose the name Athalassotoga saccharophila gen. nov., sp. nov. The type strain of the type species is NAS-01T ( = JCM 19762T = DSM 28954T). In addition, we propose a new order and family, Mesoaciditogales ord. nov. and Mesoaciditogaceae fam. nov., respectively, to accommodate the novel genus and the closely related genus Mesoaciditoga.

Gibbsiella papilionis Kim et al. 2013 is a later heterotypic synonym of Gibbsiella dentisursi Saito et al. 2013.

Synonymy of Gibbsiella dentisursi DSM 23818T ( = NUM 1720T) and Gibbsiella papilionis JCM 18389T ( = LEN33T) was suspected following multilocus sequence analysis (MLSA) of both type strains in a previous classification study, where they were found to share >99.6 % gene sequence similarity. The taxonomic relationship between these two strains was re-examined here using a polyphasic approach. A DNA-DNA hybridization value of 98 % confirmed that the two type strains belong to a single taxon, while the phenotypic profiles were found to be nearly identical. Therefore we propose Gibbsiella papilionis as a later heterotypic synonym of Gibbsiella dentisursi, with the type strain as NUM 1720T ( = DSM 23818T = JCM 17201T).

Prolixibacter denitrificans sp. nov., an iron-corroding, facultatively aerobic, nitrate-reducing bacterium isolated from crude oil, and emended descriptions of the genus Prolixibacter and Prolixibacter bellariivorans.

The facultatively aerobic, non-hydrogenotrophic, iron (Fe0)-corroding, nitrate-reducing Prolixibacter sp. strain MIC1-1(T) was characterized for representation of a novel species of the genus Prolixibacter. Strain MIC1-1(T) grew optimally at 35-37 °C, at pH 6.5 and with 2% (w/v) NaCl. Strain MIC1-1(T) also grew fermentatively on some pentoses, hexoses, disaccharides and soluble starch. Succinic acid was the major end-product from D-glucose fermentation. Strain MIC1-1(T) was differentiated from the type strain of Prolixibacter bellariivorans by cell size, optimum growth temperature, range of temperature and NaCl for growth, and nitrate reduction. On the basis of phenotypic features and the phylogenetic position, a novel species of the genus Prolixibacter is proposed for strain MIC1-1(T), to be named Prolixibacter denitrificans sp. nov. The type strain is MIC1-1(T) ( = JCM 18694(T) = NBRC 102688(T)= DSM 27267(T)). Emended descriptions of the genus Prolixibacter and Prolixibacter bellariivorans are also provided.

Iron corrosion induced by nonhydrogenotrophic nitrate-reducing Prolixibacter sp. strain MIC1-1.

Microbiologically influenced corrosion (MIC) of metallic materials imposes a heavy economic burden. The mechanism of MIC of metallic iron (Fe(0)) under anaerobic conditions is usually explained as the consumption of cathodic hydrogen by hydrogenotrophic microorganisms that accelerates anodic Fe(0) oxidation. In this study, we describe Fe(0) corrosion induced by a nonhydrogenotrophic nitrate-reducing bacterium called MIC1-1, which was isolated from a crude-oil sample collected at an oil well in Akita, Japan. This strain requires specific electron donor-acceptor combinations and an organic carbon source to grow. For example, the strain grew anaerobically on nitrate as a sole electron acceptor with pyruvate as a carbon source and Fe(0) as the sole electron donor. In addition, ferrous ion and l-cysteine served as electron donors, whereas molecular hydrogen did not. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MIC1-1 was a member of the genus Prolixibacter in the order Bacteroidales. Thus, Prolixibacter sp. strain MIC1-1 is the first Fe(0)-corroding representative belonging to the phylum Bacteroidetes. Under anaerobic conditions, Prolixibacter sp. MIC1-1 corroded Fe(0) concomitantly with nitrate reduction, and the amount of iron dissolved by the strain was six times higher than that in an aseptic control. Scanning electron microscopy analyses revealed that microscopic crystals of FePO4 developed on the surface of the Fe(0) foils, and a layer of FeCO3 covered the FePO4 crystals. We propose that cells of Prolixibacter sp. MIC1-1 accept electrons directly from Fe(0) to reduce nitrate.

Description of Mariniphaga anaerophila gen. nov., sp. nov., a facultatively aerobic marine bacterium isolated from tidal flat sediment, reclassification of the Draconibacteriaceae as a later heterotypic synonym of the Prolixibacteraceae and description of the family Marinifilaceae fam. nov.

A mesophilic, chemoheterotrophic bacterium, strain Fu11-5(T), was isolated from tidal-flat sediment from Tokyo Bay, Chiba, Japan. Cells of strain Fu11-5(T) were facultatively aerobic, Gram-negative, non-sporulating, non-motile and rod-shaped (1.9-6.9 µm long). Strain Fu11-5(T) grew optimally at 35-37 °C and pH 6.5-7.0 and with 1-2% (w/v) NaCl. Oxygen and l-cysteine were used as an alternative electron acceptor and donor, respectively. Strain Fu11-5(T) also grew fermentatively on some pentoses, hexoses and disaccharides and soluble starch. Succinic acid was the major end product from d-glucose. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain Fu11-5(T) was affiliated with the order Bacteroidales, and its nearest neighbours were members of the genera Meniscus, Prolixibacter, Sunxiuqinia, Mangrovibacterium and Draconibacterium, with 87-91% sequence similarity. Cell morphology, optimum growth temperature and utilization of sugars of strain Fu11-5(T) distinguished the strain from phylogenetically related bacteria. On the basis of its phenotypic features and phylogenetic position, a novel genus and species are proposed to accommodate strain Fu11-5(T), with the name Mariniphaga anaerophila gen. nov., sp. nov. The type strain of Mariniphaga anaerophila is strain Fu11-5(T) ( =JCM 18693(T) =NBRC 109408(T) =DSM 26910(T)). We also propose to combine the family Draconibacteriaceae into the family Prolixibacteraceae as a later heterotypic synonym and to place the distinct sublineage of the genus Marinifilum in the family Marinifilaceae fam. nov.

Corrosion of iron by iodide-oxidizing bacteria isolated from brine in an iodine production facility.

Elemental iodine is produced in Japan from underground brine (fossil salt water). Carbon steel pipes in an iodine production facility at Chiba, Japan, for brine conveyance were found to corrode more rapidly than those in other facilities. The corroding activity of iodide-containing brine from the facility was examined by immersing carbon steel coupons in "native" and "filter-sterilized" brine samples. The dissolution of iron from the coupons immersed in native brine was threefold to fourfold higher than that in the filter-sterilized brine. Denaturing gradient gel electrophoresis analyses revealed that iodide-oxidizing bacteria (IOBs) were predominant in the coupon-containing native brine samples. IOBs were also detected in a corrosion deposit on the inner surface of a corroded pipe. These results strongly suggested the involvement of IOBs in the corrosion of the carbon steel pipes. Of the six bacterial strains isolated from a brine sample, four were capable of oxidizing iodide ion (I(-)) into molecular iodine (I(2)), and these strains were further phylogenetically classified into two groups. The iron-corroding activity of each of the isolates from the two groups was examined. Both strains corroded iron in the presence of potassium iodide in a concentration-dependent manner. This is the first report providing direct evidence that IOBs are involved in iron corrosion. Further, possible mechanisms by which IOBs corrode iron are discussed.

Cellulomonas pakistanensis sp. nov., a moderately halotolerant Actinobacteria.

A rod-shaped, motile, facultatively anaerobic and moderately halotolerant plant-growth-promoting actinobacterial strain, designated NCCP-11(T), was isolated from paddy grains. To delineate its taxonomic position, the strain was subjected to a polyphasic characterization. Cells of strain NCCP-11(T) grew at 10-37 °C (optimum 28-32 °C), at pH 6-9 (optimum pH 7) and in 0-12% (w/v) NaCl (optimum 1-2%) in broth medium. Based on 16S rRNA gene sequence analysis, strain NCCP-11(T) showed highest similarity to the type strains of Cellulomonas hominis (98.99%) and Cellulomonas denverensis (98.09 %) and less than 97 % with other closely related taxa. The chemotaxonomic data [major menaquinone: MK-9(H4); cell-wall peptidoglycan: type A4ß; major fatty acids: anteiso-C15 : 0, C16 : 0, C14 : 0 and anteiso-C17 : 0; major polar lipids: diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositolmannosides and two unknown polar lipids] also supported the affiliation of strain NCCP-11(T) to the genus Cellulomonas. The level of DNA-DNA relatedness between strain NCCP-11(T) and the two type strains mentioned above was less than 42.7%. On the basis of DNA-DNA relatedness, physiological and biochemical characteristics and phylogenetic position, strain NCCP-11(T) can be differentiated from species of the genus Cellulomonas with validly published names and thus represents a novel species, for which the name Cellulomonas pakistanensis sp. nov. is proposed. The type strain is NCCP-11(T) ( = DSM 24792(T) = JCM 18755(T) = KCTC 19798(T)).

Mobilicoccus pelagius gen. nov., sp. nov. and Piscicoccus intestinalis gen. nov., sp. nov., two new members of the family Dermatophilaceae, and reclassification of Dermatophilus chelonae (Masters et al. 1995) as Austwickia chelonae gen. nov., comb. nov.

Two Gram-positive bacteria, designated strains Aji5-31(T) and Ngc37-23(T), were isolated from the intestinal tracts of fishes. 16S rRNA gene sequence analysis indicated that both strains were related to the members of the family Dermatophilaceae, with 95.6-96.9% 16S rRNA gene sequence similarities. The family Dermatophilaceae contains 2 genera and 3 species: Dermatophilus congolensis, Dermatophilus chelonae and Kineosphaera limosa. However, it has been suggested that the taxonomic position of D. chelonae should be reinvestigated using a polyphasic approach, because the chemotaxonomic characteristics are not known (Stackebrandt, 2006; Stackebrandt and Schumann, 2000). Our present study revealed that strains Aji5-31(T), Ngc37-23(T) and D. chelonae NBRC 105200(T) should be separated from the other members of the family Dermatophilaceae on the basis of the following characteristics: the predominant menaquinone of strain Aji5-31(T) is MK-8(H(2)), strain Ngc37-23(T) possesses iso- branched fatty acids as major components, and the menaquinone composition of D. chelonae is MK-8(H(4)), MK-8 and MK-8(H(2)) (5 : 3 : 2, respectively). On the basis of these distinctive phenotypic characteristics and phylogenetic analysis results, it is proposed that strains Aji5-31(T) and Ngc37-23(T) be classified as two novel genera and species of the family Dermatophilaceae. The names are Mobilicoccus pelagius gen. nov., sp. nov. and Piscicoccus intestinalis gen. nov., sp. nov., and the type strains are Aji5-31(T) (=NBRC 104925(T) =DSM 22762(T)) and Ngc37-23(T) (=NBRC 104926(T) =DSM 22761(T)), respectively. In addition, D. chelonae should be reassigned to a new genus of the family Dermatophilaceae with the name Austwickia chelonae gen. nov., comb. nov.

Persicobacter psychrovividus sp. nov., isolated from shellfish, and emended descriptions of the genus Persicobacter and Persicobacter diffluens.

The taxonomic position of three bacterial strains, Asr22-19T, NBRC 101035 and NBRC 101041, isolated from shellfish in Japan, was determined by using a polyphasic taxonomic approach. The strains were facultatively anaerobic, motile by gliding and Gram-staining-negative slender rods. Their major respiratory quinone was menaquinone-7 and their predominant cellular fatty acids were iso-C15:0, iso-C17:0 3-OH, iso-C15:0 3-OH, C16:0 3-OH, and C16:0. The G+C content of the genomic DNA was 42.0-42.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strains clustered with the genus Persicobacter in the family 'Flammeovirgaceae'. DNA-DNA relatedness values were higher than 68% among strains Asr22-19T, NBRC 101035 and NBRC 101041, and were lower than 28% between strain Asr22-19T and Persicobacter diffluens NBRC 15940T. The three novel strains could be differentiated from Persicobacter diffluens by several phenotypic characteristics. On the basis of these results, the novel species Persicobacter psychrovividus sp. nov. (type strain Asr22-19T=NBRC 101262T=CIP 109100T) is proposed and emended descriptions are given for the genus Persicobacter and for Persicobacter diffluens.

Serinibacter salmoneus gen. nov., sp. nov., an actinobacterium isolated from the intestinal tract of a fish, and emended descriptions of the families Beutenbergiaceae and Bogoriellaceae.

A novel Gram-positive bacterium, designated Kis4-28(T), was isolated from the intestinal tract of a fish, and its taxonomic position was investigated by a polyphasic approach. The sample was collected from the coast of Tokyo Bay, Japan. Cells of strain Kis4-28(T) were rod-shaped, non-motile and non-sporulating. The peptidoglycan type of the isolate was A4alpha; lysine was the diagnostic diamino acid. The only menaquinone detected was MK-8(H(4)), and the major fatty acids were anteiso-C(15 : 0) and C(16 : 0). Galactose was detected as a major cell-wall sugar. The polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content was 70.7 mol%. 16S rRNA gene sequence analysis revealed that strain Kis4-28(T) and the type strain of Salana multivorans formed a monophyletic cluster with a 16S rRNA gene sequence similarity of 96.2 %. Strain Kis4-28(T) was clearly distinguishable from the genus Salana in terms of its chemotaxonomic characteristics. On the basis of the genotypic and phenotypic characteristics, a new genus and species is proposed for strain Kis4-28(T), with the name Serinibacter salmoneus gen. nov., sp. nov. The type strain of Serinibacter salmoneus is Kis4-28(T) (=NBRC 104924(T) =DSM 21801(T)). In addition, on the basis of 16S rRNA gene sequence analysis of the genus Serinibacter and related genera, emended descriptions of the families Beutenbergiaceae and Bogoriellaceae are proposed to accommodate the genera Beutenbergia, Salana and Serinibacter, and the genera Bogoriella and Georgenia, respectively.

Lacticigenium naphtae gen. nov., sp. nov., a halotolerant and motile lactic acid bacterium isolated from crude oil.

A novel lactic acid bacterium, strain MIC1-18(T), was isolated from crude oil collected at an oil-water well in Akita, Japan. Cells of strain MIC1-18(T) were found to be facultatively anaerobic, mesophilic, neutrophilic, Gram-negative, non-sporulating, motile by means of peritrichous flagella and oval rods, 1.8-2.5 mum long. Optimum growth was observed at 30 degrees C, pH 7.0 and 3 % (w/v) NaCl. Strain MIC1-18(T) produced acid from l-arabinose, ribose, glucose, fructose, mannose, N-acetylglucosamine, amygdalin, arbutin, salicin, cellobiose, maltose, sucrose, trehalose, gentiobiose and 5-ketogluconate. l-Lactic acid was the major end product from glucose. The major cellular fatty acid was C(16 : 1)omega7c. The cell-wall murein type was A4alpha containing Lys-Glu. The G+C content of the genomic DNA was 37.8 mol%. Phylogenetic analysis based on the 16S rRNA gene revealed that strain MIC1-18(T) was accommodated as a member of the lactic acid bacteria of the low-G+C content Gram-positive bacteria; the closest neighbour of this organism was Atopococcus tabaci CCUG 48253(T), with only 90.0 % sequence similarity. On the basis of the phenotypic features and phylogenetic position, a novel genus and species, Lacticigenium naphtae gen. nov., sp. nov., are proposed for strain MIC1-18(T) (=NBRC 101988(T)=DSM 19658(T)).

Ferrimonas futtsuensis sp. nov. and Ferrimonas kyonanensis sp. nov., selenate-reducing bacteria belonging to the Gammaproteobacteria isolated from Tokyo Bay.

Two novel mesophilic, facultatively anaerobic, selenate-reducing bacteria, designated strains FUT3661T and Asr22-7T, were isolated from a sediment sample and the alimentary tract of littleneck clams, respectively. Both sources of the samples were collected from the coast of Tokyo Bay, Japan. Cells were Gram-negative rods and motile by means of a polar flagellum. The strains reduced selenate to elemental selenium (Se0) and also reduced iron(III) oxyhydroxide, iron(III) citrate, arsenate, manganese(IV) oxide, elemental sulfur and oxygen and used lactate, pyruvate, yeast extract, tryptone and Casamino acids as electron donors and carbon sources. The strains contained both menaquinone (MK-7) and ubiquinones (Q-7 and Q-8) as isoprenoid quinones. The major fatty acids were C16:0 and C16:1omega9c. The G+C content of the genomic DNA was 58.1 mol% for strain FUT3661T and 57.2 mol% for strain Asr22-7T. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strains were related to members of the genus Ferrimonas (<94.0% similarities), although the two novel strains formed a separate lineage. 16S rRNA gene sequence similarity between strains FUT3661T and Asr22-7T was 96%. On the basis of this polyphasic analysis, it was concluded that strains FUT3661T and Asr22-7T represent two novel species within the genus Ferrimonas, for which the names Ferrimonas futtsuensis sp. nov. (type strain FUT3661T=NBRC 101558T=DSM 18154T) and Ferrimonas kyonanensis sp. nov. (type strain Asr22-7T=NBRC 101286T=DSM 18153T) are proposed.