title: Methanocalculus pumilus sp. nov., a heavy-metal-tolerant methanogen isolated from a waste-disposal site.
abstract: A mesophilic hydrogenotrophic methanogen, strain MHT-1T, was isolated from the leachate of a sea-based site for solid waste disposal (the port of Osaka, Japan). Strain MHT-1T was found to be an irregular coccus and was able to use H2/CO2 and formate as energy sources. Acetate was required for growth. The optimum temperature and pH for growth were 35 degrees C and 6.5-7.5, respectively. Strain MHT-1T was resistant to high concentrations of several heavy metals such as CdCl2 and CuSO4. The G+C content of the DNA was 51.9 mol%. Analysis of the 16S rRNA gene revealed that the isolate was a member of the genus Methanocalculus but distinct from its nearest neighbour, Methanocalculus halotolerans, there being a sequence similarity of 98.9%. DNA-DNA hybridization analysis revealed 51% relatedness with the DNA of M. halotolerans strain SEBR 4845T. The optimum NaCl concentration was 1.0%, whereas the optimum in M. halotolerans was 5.0%. A new species, Methanocalculus pumilus, is proposed for strain MHT-1T. The type strain is MHT-1T (= DSM 12632T = JCM 10627T).
authors.forename: K
authors.initials: K
authors.lastname: Mori
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Kamagata
authors.forename: M
authors.initials: M
authors.lastname: Hatsu
authors.forename: K
authors.initials: K
authors.lastname: Takamizawa
mesh_terms: D001482:Base Composition; D003470:Culture Media; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D019216:Metals, Heavy / Q000378:metabolism / Q000494:pharmacology*; D008697:Methane / Q000378:metabolism; D019638:Methanomicrobiaceae / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012037:Refuse Disposal; D012623:Seawater; D017422:Sequence Analysis, DNA
chemical_list: D003470:Culture Media; D019641:DNA, Archaeal; D019216:Metals, Heavy; D012336:RNA, Ribosomal, 16S; D008697:Methane