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.

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.

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.

Iron corrosion activity of anaerobic hydrogen-consuming microorganisms isolated from oil facilities.

The purpose of the present study was to test the hypothesis that anaerobic hydrogen-consuming microorganisms generally promote iron corrosion. We isolated 26 hydrogen-consuming microorganisms (acetogens, sulfate-reducing bacteria, and methanogens) from oil facilities in Japan using hydrogen as an electron donor. The iron corrosion activities of these microorganisms were examined using iron (Fe0) granules as the sole electron donor. Almost all the isolates consumed hydrogen that was chemically generated from iron granules but did not induce significant iron corrosion. The amount of corroded iron in the cultures of these organisms was less than 2-fold that in an abiotic chemical corrosion reaction. These results indicated that hydrogen consumption did not strongly stimulate iron corrosion. On the other hand, one isolate, namely, Methanococcus maripaludis Mic1c10, considerably corroded iron: this phenomenon was not accompanied by hydrogen consumption, methane formation, or cell growth. This finding also provided strong evidence that M. maripaludis Mic1c10 produced some material that caused iron to corrode.

Iron-corroding methanogen isolated from a crude-oil storage tank.

Microbiologically influenced corrosion of steel in anaerobic environments has been attributed to hydrogenotrophic microorganisms. A sludge sample collected from the bottom plate of a crude-oil storage tank was used to inoculate a medium containing iron (Fe(0)) granules, which was then incubated anaerobically at 37 degrees C under an N(2)-CO(2) atmosphere to enrich for microorganisms capable of using iron as the sole source of electrons. A methanogen, designated strain KA1, was isolated from the enrichment culture. An analysis of its 16S rRNA gene sequence revealed that strain KA1 is a Methanococcus maripaludis strain. Strain KA1 produced methane and oxidized iron much faster than did the type strain of M. maripaludis, strain JJ(T), which produced methane at a rate expected from the abiotic H(2) production rate from iron. Scanning electron micrographs of iron coupons that had been immersed in either a KA1 culture, a JJ(T) culture, or an aseptic medium showed that only coupons from the KA1 culture had corroded substantially, and these were covered with crystalline deposits that consisted mainly of FeCO(3).

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.

Euzebya tangerina gen. nov., sp. nov., a deeply branching marine actinobacterium isolated from the sea cucumber Holothuria edulis, and proposal of Euzebyaceae fam. nov., Euzebyales ord. nov. and Nitriliruptoridae subclassis nov.

A tangerine-coloured, Gram-positive actinobacterial strain, designated F10(T), was isolated from the abdominal epidermis of a sea cucumber, Holothuria edulis, collected in seawater off the coast of Japan. A 16S rRNA gene sequence analysis indicated that strain F10(T) was a member of the class Actinobacteria and was most closely related to Nitriliruptor alkaliphilus ANL-iso2(T) (87.4 % sequence similarity). Phylogenetic analyses showed that strain F10(T) represented a novel, deep-rooted, and distinct phylogenetic lineage within the class Actinobacteria and clustered with N. alkaliphilus and uncultured bacteria. The organism had meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan, and rhamnose and galactose as the diagnostic cell-wall sugars. Strain F10(T) contained C16 :0ω7c, C16:0 and C17:1ω8c as the major cellular fatty acids. The predominant isoprenoid quinone was MK-9 (H4).The G+C content of the DNA was 68.3 mol%. Based on data from the current polyphasic study, it is proposed that the new marine isolate be placed in a novel genus and be considered a novel species designated Euzebya tangerina gen. nov., sp. nov. within the new family, order and subclass Euzebyaceae fam. nov., Euzebyales ord. nov. and Nitriliruptoridae subclassis nov. in the class Actinobacteria. The type strain of Euzebya tangerina is F10(T) (=NBRC 105439(T) =KCTC 19736(T)).

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.

Physicochemical characters of a tyrosinase inhibitor produced by Streptomyces roseolilacinus NBRC 12815.

We examined the biological activities present in Streptomyces strains preserved at the National Institute of Technology and Evaluation Biological Resource Center, and found a metabolite of Streptomyces roseolilacinus NBRC 12815 that showed a potent anti-tyrosinase activity. The compounds with anti-tyrosinase activity were purified by several chromatographic procedures. Final HPLC analysis revealed at least two anti-tyrosinase compounds with different retention times (12815A and B). The identification of two anti-tyrosinase compounds was performed with instrumental analysis and database search. The results obtained suggest that the active compounds are SF 2583A and B. Compound 12815A (IC(50) values; about 9 microM) showed more potent tyrosinase inhibition than compound 12815B (IC(50) values; about 1086 microM). The only structural difference between 12815A and B is the presence of an additional chloric atom. In addition, the activity of 12815A was markedly decreased under acidic conditions, resulting in irreversible inactivation. However, the inactivated 12815A still exhibited residual activity when exposed to detergent, Tween 80. These results suggest that the chlorine and the hydration water are very important in the exertion of anti-tyrosinase activity by 12815A.

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)).

Acanthopleuribacter pedis gen. nov., sp. nov., a marine bacterium isolated from a chiton, and description of Acanthopleuribacteraceae fam. nov., Acanthopleuribacterales ord. nov., Holophagaceae fam. nov., Holophagales ord. nov. and Holophagae classis nov. in the phylum 'Acidobacteria'.

Strain FYK2218(T) was isolated from a specimen of the chiton Acanthopleura japonica, which had been collected from a beach on the Boso peninsula in Japan. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the strain belonged to the phylum 'Acidobacteria'. The most closely related type strains to strain FYK2218(T) were Holophaga foetida TMBS4(T) (83.6 % 16S rRNA gene sequence similarity) and Geothrix fermentans H-5(T) (83.6 %) in subdivision 8 of the 'Acidobacteria'. Cells of FYK2218(T) were motile, rod-shaped, Gram-negative, mesophilic and strictly aerobic. The G+C content of the strain was 56.7 mol%. The strain had isoprenoid quinones MK-6 and MK-7 as major components. Major fatty acids of the strain were iso-C(15 : 0), iso-C(17 : 0), C(16 : 0) and C(20 : 5)omega3c (cis-5,8,11,14,17-eicosapentaenoic acid). From the taxonomic data obtained in this study, it is proposed that the new marine isolate be placed into a novel genus and species named Acanthopleuribacter pedis gen. nov., sp. nov. within the new family, order and class Acanthopleuribacteraceae fam. nov., Acanthopleuribacterales ord. nov. and Holophagae classis nov. The family Holophagaceae fam. nov. is also described. The type strain of Acanthopleuribacter pedis is FYK2218(T) (=NBRC 101209(T) =KCTC 12899(T)).

Taxonomic distribution of Streptomyces species capable of producing bioactive compounds among strains preserved at NITE/NBRC.

The taxonomic distribution of Streptomyces species capable of producing bioactive compounds was investigated. Nine hundred and six strains were tested for the following four biological activities: antimicrobial, anti-tyrosinase, antioxidant, and hemolytic. Approximately 30% of strains tested showed antimicrobial activities, except for anti-Escherichia coli activity, which was present in only a few strains, while the rates of positivity for the anti-tyrosinase, antioxidant, and hemolytic activities were much lower. The distribution of Streptomyces strains capable of producing bioactive compounds was analyzed by the taxonomy based on 16S rRNA gene sequences. Moreover, the strains of Streptomyces hygroscopicus tested were divided into two clades in the phylogenetic tree, and all of the strains belonging to one clade showed antibacterial and antifungal activities. For detection of polyenes, the UV-visible spectra of metabolic extracts in the strains showing antifungal activities were measured. It was suggested that Streptomyces strains produce universal active compounds under different growth conditions. Further information on the relationship between the microbial taxonomy and the bioactive compounds produced would be useful for the utilization of industrial microorganisms.

Emended descriptions of the genus Lewinella and of Lewinella cohaerens, Lewinella nigricans and Lewinella persica, and description of Lewinella lutea sp. nov. and Lewinella marina sp. nov.

Two strains, MKG-38(T) and FYK2402M69(T), were isolated from a marine sediment sample and a sea snail, respectively, both collected on the Pacific coast of Japan. Phylogeny of these new isolates based on 16S rRNA gene sequences indicated that they are members of the genus Lewinella. Morphological, physiological and biochemical properties of these two isolates, together with the type strains of the three previously described species of the genus Lewinella, were characterized. The new isolates were Gram-negative, aerobic, rod-shaped, chemo-organotrophic and able to degrade starch and CM-cellulose. A comparative polyphasic study showed that these two isolates represent two novel species of the genus Lewinella, for which the names Lewinella marina sp. nov. (type strain, MKG-38(T)=NBRC 102633(T)=NCIMB 14312(T)) and Lewinella lutea sp. nov. (type strain, FYK2402M69(T)=NBRC 102634(T)=NCIMB 14313(T)) are proposed. Emended descriptions of the genus Lewinella (Sly et al. 1998) and of Lewinella cohaerens, Lewinella nigricans and Lewinella persica are also proposed.

Nocardia amamiensis sp. nov., isolated from a sugar-cane field in Japan.

An actinomycete, strain TT 00-78(T), was isolated from soil from a sugar-cane field on Amami Island in Japan, using an SDS/yeast extract pre-treatment method, and the taxonomy was studied using a polyphasic approach. The chemotaxonomic and morphological characterizations clearly demonstrated that the strain belongs to the genus Nocardia. 16S rRNA gene sequencing studies showed that the strain was closely related to the type strains of Nocardia pneumoniae (98.6 %), Nocardia araoensis (98.1 %), Nocardia arthritidis (97.9 %) and Nocardia beijingensis (97.7 %). However, the results of DNA-DNA hybridization and physiological and biochemical tests showed that strain TT 00-78(T) could be differentiated from its closest phylogenetic relatives both genotypically and phenotypically. Therefore this strain represents a novel species of the genus Nocardia, for which the name Nocardia amamiensis sp. nov. is proposed. The type strain is TT 00-78(T) (=NBRC 102102(T)=DSM 45066(T)=KCTC 19208(T)).

Method for selective isolation of Mycobacteria using olive oil emulsified with SDS.

This paper describes the demulsification of olive-oil/SDS emulsion (DOSE) method for selective isolation of environmental mycobacteria. A soil sample was suspended in olive oil and centrifuged. The supernatant was emulsified on plates together with SDS solution. After incubation, the colonies that had developed on the plates were surrounded by clear zones. The isolates were identified as genus Mycobacterium, and as belonging to a fast-growing group, by 16S rRNA gene sequence analysis.

New aureothin derivative, alloaureothin, from Streptomyces sp. MM23.

A new polypropionate alloaureothin (1) possessing a nitro group, together with a known polypropionate aureothin (2), was isolated from mycelium of Streptomyces sp. MM23. The structure was determined on the basis of spectroscopic data. 1 exhibited growth inhibitory effect against human fibrosarcoma HT1080 cells with an IC50 value of 30 microM.

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.

Sandarakinotalea sediminis gen. nov., sp. nov., a novel member of the family Flavobacteriaceae.

Four Gram-negative, orange-coloured, aerobic, heterotrophic bacteria were isolated from sediment samples collected on the Pacific coast of Japan near the cities of Toyohashi and Katsuura. 16S rRNA gene sequence analysis indicated that these strains form a distinct lineage within the family Flavobacteriaceae. The four isolates shared 99.9-100 % 16S rRNA gene sequence similarity with each other and showed 88-90.9 % similarity with their neighbours in the family Flavobacteriaceae. The four strains also shared high DNA-DNA reassociation values of 67-99 % with each other. All the strains grew at 37 degrees C but not at 4 degrees C, and degraded gelatin, starch and DNA. The major fatty acids were i-C15:0, a-C15:0, i-C16:0 and i-C17:0 3-OH. However, two common fatty acids of members of the Flavobacteriaceae, i-C15:1 and a-C15:1, were absent in these strains. The DNA G+C contents of the four strains were in the range 35-37 mol%. On the basis of the polyphasic evidence, it was concluded that these strains should be classified as a novel genus and a novel species in the family Flavobacteriaceae, for which the name Sandarakinotalea sediminis gen. nov., sp. nov. is proposed. The type strain of Sandarakinotalea sediminis is CKA-5T (=NBRC 100970T=LMG 23247T).

Microbial communities in oil-contaminated seawater.

Although diverse bacteria capable of degrading petroleum hydrocarbons have been isolated and characterized, the vast majority of hydrocarbon-degrading bacteria, including anaerobes, could remain undiscovered, as a large fraction of bacteria inhabiting marine environments are uncultivable. Using culture-independent rRNA approaches, changes in the structure of microbial communities have been analyzed in marine environments contaminated by a real oil spill and in micro- or mesocosms that mimic such environments. Alcanivorax and Cycloclasticus of the gamma-Proteobacteria were identified as two key organisms with major roles in the degradation of petroleum hydrocarbons. Alcanivorax is responsible for alkane biodegradation, whereas Cycloclasticus degrades various aromatic hydrocarbons. This information will be useful to develop in situ bioremediation strategies for the clean-up of marine oil spills.