Complete genome sequence of the hydrogenotrophic Archaeon Methanobacterium sp. Mb1 isolated from a production-scale biogas plant

•First genome sequence of a Methanobacterium sp. isolate from a production-scale biogas plant is reported.•Methanobacterium sp. Mb1 represents a new species within the genus Methanobacterium.•The Methanobacterium sp. Mb1 genome is the smallest genome known so far within the genus Methanobacterium. Methanobacterium sp. Mb1, a hydrogenotrophic methanogenic Archaeon, was isolated from a rural biogas plant producing methane-rich biogas from maize silage and cattle manure in Germany. Here we report the complete genome sequence of the novel methanogenic isolate Methanobacterium sp. Mb1 harboring a 2,029,766bp circular chromosome featuring a GC content of 39.74%. The genome encodes two rRNA operons, 41 tRNA genes and 2021 coding sequences and represents the smallest genome currently known within the genus Methanobacterium.