sp. nov., a methanogenic archaeon isolated from a full-scale anaerobic digester.

A novel, strictly anaerobic, methanogenic archaeon, strain E03.2, was isolated from a full-scale biogas plant in Germany. Cells were non-motile sarcina-like cocci, occurring in aggregates. Strain E03.2 grew autotrophically on H plus CO, and additionally cells could utilize acetate, methanol, moni-, di- and trimethylamine as carbon and energy sources; however, growth or methanogenesis on formate was not observed. Yeast extract and vitamins stimulated growth but were not mandatory. The optimal growth temperature of strain E03.2 was approximately 45 °C; maximal growth rates were obtained at about pH 7.0 in the presence of approximately 6.8 mM NaCl. The DNA G+C content of strain E03.2 was 41.3 mol%. Phylogenetic analyses based on 16S rRNA gene and sequences placed strain E03.2 within the genus . Based on 16S rRNA gene sequence similarity strain E03.2 was related to seven different species of the genus , but most closely related to TM-1. Phenotypic, physiological and genomic characteristics indicated that strain E03.2 represents a novel species of the genus , for which the name sp. nov. is proposed. The type strain is E03.2 ( = DSM 100822 = JCM 30921).