Methanobacterium beijingense sp. nov., a novel methanogen isolated from anaerobic digesters

Abstract

Two methanogenic strains, 8-2T and 4-1, with rod-shaped (0·4–0·5×3–5 μm), non-motile cells, sometimes observed in chains, were isolated from two anaerobic digesters in Beijing, China. The two strains used H2/CO2 and formate for growth and produced methane. The temperature range for growth was 25–50 °C, with fastest growth at 37 °C. The pH ranges for growth and methane production were 6·5–8·0 for strain 8-2T and 6·8–8·6 for strain 4-1, with the fastest growth at pH 7·2 for strain 8-2T and pH 7·5–7·7 for strain 4-1. The G+C content of genomic DNA for strain 8-2T was 38·9 mol%. The similarity levels of the 16S rRNA sequence of strain 8-2T with other species of the genus Methanobacterium ranged from 93·8 to 96·0 %. Based on the phylogenetic analysis and phenotypic characteristics, the novel species Methanobacterium beijingense sp. nov. is proposed, with the type strain 8-2T (=DSM 15999T=CGMCC 1.5011T).