Nakata E.,Japan Central Research Institute of Electric Power Industry |
Tanaka S.,Japan Central Research Institute of Electric Power Industry |
Suenaga H.,Japan Central Research Institute of Electric Power Industry |
Mahara Y.,Kyoto University |
And 3 more authors.
Applied Geochemistry | Year: 2012
Gas was sampled regionally, including by drilling into faults, in the South Kanto gas-field around Tokyo Bay, Japan. Gas samples were collected from cores in a gas sampling container immediately after drilling. A value of δ 13C 1=-44.3‰ was obtained for gas in the container and δ 13C 1=-36.3‰ for seeping gas in a fault zone. However, typical CH 4 in this dissolved-in-water gas-field is mainly depleted in 13C, and δ 13C 1 values range from -66‰ to -68‰ owing to microbial degradation of organic material. 13C-rich CH 4 is so far uncommon in the South Kanto gas-field. Seepages were observed from the surface along the north-south fault zone. The natural gas is stored below the sandstone layer by impermeable mudstone underlying the boundary at a depth of 30m. Gas seepages were not observed below a depth of 40m. Gas rises along the fault zone dissolved-in-groundwater up to the shallow region and then separates from the groundwater. 13C-rich CH 4 (adsorbed CH 4) was found to have desorbed from drilled mudstone core samples taken at depths of 1400-1900m in the main gas-production strata. Similarly, 13C-rich CH 4 was found in black shale overlying the oceanic crust forming part of a sedimentary accretionary prism underling the Tokyo region. It also appears in the spring-water of spa wells, originating at a depth of 1200-1500m along a tectonic line. Methane generated by microbial degradation of organic material through CO 2 reduction in the South Kanto gas-field mainly originates as biogenic gas mixed with a small amount of 13C-rich CH 4, derived from thermogenic gas without oil components in strata. It is assumed that 12C-rich CH 4 is easily detached from core or pore water through gas production, whereas 13C-rich CH 4 is strongly adsorbed on the surfaces of particles. The 13C-rich CH 4 rises along the major tectonic line or up the 50m wide normal fault zone from relatively deep sources in the Kanto region. © 2012.
Hirayama H.,Japan Agency for Marine - Earth Science and Technology |
Fuse H.,Shibaura Institute of Technology |
Abe M.,Japan Agency for Marine - Earth Science and Technology |
Miyazaki M.,Japan Agency for Marine - Earth Science and Technology |
And 5 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2013
Two aerobic methane-oxidizing bacterial strains were isolated from distinct marine environments in Japan. Strains IT-4 T and T2-1 were Gram-stain-negative, aerobic, motile, plump short rods or oval-shaped bacteria with a single polar flagellum and type I intracytoplasmic membranes. They were obligate methanotrophs that grew only on methane or methanol. Each strain possessed the particulate methane monooxygenase (pMMO). The ribulose monophosphate pathway was operative for carbon assimilation. The strains grew best at 37 °C, and did not grow at 45 °C. NaCl was required for growth within a concentration range of 1-8 % (w/v). The major phospholipid fatty acids were C 16: 0, C 16: 1ω7c, and C 16: 1ω5t. The major isoprenoid quinone was MQ-8. The DNA G+C content was 50.9-51.7 mol%. The 16S rRNA gene sequences of the strains showed 99.4 % similarity to each other, and DNA-DNA hybridization analysis indicated that the strains were representatives of the same species. The 16S rRNA gene sequences were highly similar to some marine environmental sequences (94.0-97.7 % similarity), but did not show similarities more than 94 % with sequences of members of other related genera, such as Methylomicrobium, Methylobacter, Methylomonas and Methylosarcina. Phylogenies based on 16S rRNA gene sequences and deduced partial PmoA sequences, and the physiological and chemotaxonomic characteristics revealed that strains IT-4 T and T2-1 represent a novel species of a new genus in the family Methylococcaceae, for which the name Methylomarinum vadi gen. nov., sp. nov. is proposed. The type strain is IT-4 T (= JCM 13665 T = DSM 18976 T). © 2013 IUMS.
Suzuki T.,Shibaura Institute of Technology |
Nakamura T.,Chugai Technos Co. |
Fuse H.,Shibaura Institute of Technology
Microbes and Environments | Year: 2011
Two novel ethylene-assimilating bacteria, strains ETY-M and ETY-NAG, were isolated from seawater around Japan. The characteristics of both strains were investigated, and phylogenetic analyses of their 16S rRNA gene sequences showed that they belonged to the genus Haliea. In C1-4 gaseous hydrocarbons, both strains grew only on ethylene, but degraded ethane, propylene, and propane in addition to ethylene. Methane, n-butane, and i-butane were not utilized or degraded by either strain. Soluble methane monooxygenase-type genes, which are ubiquitous in alkene-assimilating bacteria for initial oxidation of alkenes, were not detected in these strains, although genes similar to particulate methane monooxygenases (pMMO)/ammonia monooxygenases (AMO) were observed. The phylogenetic tree of the deduced amino acid sequences formed a new clade near the monooxygenases of ethane-assimilating bacteria similar to other clades of pMMOs in type I, type II, and Verrucomicrobia methanotrophs and AMOs in alpha and beta proteobacteria.
Yamauchi T.,Toyama Institute of Health |
Yoshigou H.,Chugai Technos Co. |
Itoh T.,Marine Biological Research Institute of Japan Co.
Comparative Parasitology | Year: 2013
ABSTRACT: We present the first record of Parabdella quadrioculata (Annelida: Hirudinida: Glossiphoniidae) from Japan. Leeches were collected from the Japanese pond turtle Mauremys japonica and a Japanese man. Mauremys japonica is a new host for this leech. This report is the first case of human infestation by the glossiphoniid leech.
Mori R.,Kyushu University |
Sugai Y.,Kyushu University |
Sasaki K.,Kyushu University |
Fujiwara K.,Chugai Technos Co.
Society of Petroleum Engineers - SPE Asia Pacific Oil and Gas Conference and Exhibition 2011 | Year: 2011
We are focusing on in-situ microbial conversion of CO 2 that was injected into depleted oil reservoirs for CCS into CH 4 by oil-degrading and H 2-producing bacteria and hydrogenotrophic methanogens. Those bacteria are concerned to be affected under high CO 2 condition, which causes pH reduction of the brine; therefore, we estimated the possibility of this microbial conversion process under high partial pressure of CO 2 in this study by investigating the following: - The habitations of above bacteria in a high/low CO 2 content reservoir - The pH reduction of brine under high partial pressure of CO 2 - Productivities of H 2 and CH 4 by indigenous bacteria of the high CO 2 content reservoirs Thermotoga sp. and Thermoanaerobacter sp. whose productivities of hydrogen from crude oil had been shown by Fujiwara et al. 1) were detected as a dominant in the high CO 2 content reservoir. Moreover, Methanobacterium sp. and Methanothermobacter sp. that are well known as hydrogenotrophic methanogens were also detected from the reservoir. These results indicate that the effective microorganisms for this microbial conversion process can inhabit reservoirs that stored with CO 2 for CCS dominantly. The pH of the brine including bicarbonate more than 0.1 mol/L can be maintained at 7.0 to 8.0, which was suitable pH for many kinds of microorganisms, even under high CO 2 partial pressure such as 5.0 MPa, suggesting that this microbial conversion process can be applied easily on reservoirs whose brine is abundant in bicarbonate. Enrichment culture experiments of the brine were carried out under high CO 2 partial pressure (3.0 MPa) at 75°C. Both H 2 and CH 4 production were found in not only the brine having the pH buffering action but also the brine whose pH was reduced significantly under high CO 2 partial pressure; therefore, the microbial conversion process may be also expected in normal reservoirs that have poor acid neutralizing capacity. Copyright 2011, Society of Petroleum Engineers.