Methanolobus zinderi sp. nov., a methylotrophic methanogen isolated from a deep subsurface coal seam

A methanogenic organism from the domain Archaea (SD1^T) was isolated from saline water released from a coal seam located 926 m below the surface via a methane-producing well near Monroe, Louisiana, USA. Growth and methanogenesis were supported with methanol, monomethylamine, dimethylamine or trimethylamine, but not with dimethylsulfide, formate, acetate or H₂/CO₂. Cells grew in high-salt minimal medium but growth was stimulated with yeast extract or tryptone. Cells were single, non-motile, irregular coccoids 0.5-1.0 μm in diameter and the cell wall contained protein. Conditions for the maximum rate of growth were 40-50 °C, 0.2-0.6 M NaCl, 100-≥200 mM MgCl₂, and pH 7.0-8.0. The G+C content of the genomic DNA was 42 ± 1 mol%. A comparison of 16S rRNA gene sequences indicated that strain SD1^T was most closely related to Methanolobus oregonensis DSM 5435^T with 96% gene sequence similarity. It is proposed that strain SD1^T represents a novel species, Methanolobus zinderi sp. nov. The type strain is SD1^T (=ATCC BAA-1601^T=DSM 21339^T).