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

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

© 2015 IUMS. 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)

<Preliminary>The Effect of Auxin on the Polarity of Tracheid Arrangement in Pinus Thunbergii

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Aceticlastic and NaCl-Requiring Methanogen "Methanosaeta pelagica" sp. nov., Isolated from Marine Tidal Flat Sediment

Acetate is a key compound for anaerobic organic matter degradation, and so far, two genera, Methanosaeta and Methanosarcina, are only contributors for acetate degradation among methanogens. An aceticlastic methanogen, designated strain 03d30qT, was isolated from a tidal flat sediment in Futtsu, Japan. The phylogenetic analyses based on 16S rRNA and mcrA genes revealed that the isolate belonged to the genus Methanosaeta, but the optimal Na+ concentration for growth shifted to marine environments unlike the other known Methanosaeta species. The quantitative estimation by using a real-time PCR indicated that the 16S rRNA gene of the genus Methanosaeta was detected in the sediments and the relative abundance ranged from 3.9% to 11.8% of the total archaeal 16S rRNA genes. Also, the amount of the genus Methanosaeta increased with increasing depth and was much higher than that of the genus Methanosarcina. This is the first report of marine Methanosaeta species, and on the basis of phylogenetic and characteristic studies, the novel species is proposed, "Methanosaeta pelagica" sp. nov., with types strain 03d30qT

Algoriphagus sanaruensis sp. nov., a member of the family Cyclobacteriaceae, isolated from a brackish lake in Hamamatsu, Japan

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