Methanosarcina soligelidi sp. nov., a desiccation- and freeze-thaw-resistant methanogenic archaeon from a Siberian permafrost-affected soil

Abstract

A methanogenic archaeon, strain SMA-21T, was isolated from a permafrost-affected soil by serial dilution in liquid medium. The cells were non-motile, stained Gram-negative and grew as irregular cocci with a diameter of 1.3–2.5 µm. Optimal growth was observed at 28 °C, pH 7.8 and 0.02 M NaCl. The strain grew on H2/CO2, methanol and acetate, but not on formate, ethanol, 2-butanol, 2-propanol, monomethylamine, dimethylamine, trimethylamine or dimethyl sulfide. Major membrane lipids of strain SMA-21T were archaeol phosphatidylglycerol, archaeol phosphatidylethanolamine and the corresponding hydroxyarchaeol compounds. The G+C content of the genomic DNA was 40.9 mol%. The 16S rRNA gene sequence was closely related to those of Methanosarcina mazei DSM 2053T (similarity 99.9 %) and Methanosarcina horonobensis HB-1T (similarity 98.7 %). On basis of the level of DNA–DNA hybridization (22.1 %) between strain SMA-21T and Methanosarcina mazei DSM 2053T as well as of phenotypic and genotypic differences, strain SMA-21T was assigned to a novel species of the genus Methanosarcina , for which the name Methanosarcina soligelidi sp. nov. is proposed. The type strain is SMA-21T ( = DSM 20065T = JCM 18468).