Moorella caeni sp. nov., isolated from thermophilic anaerobic sludge from a methanol-fed reactor

Strain AMP^T has been previously suggested as a strain of the species Moorella thermoacetica Jiang et al. 2009 (based on the high 16S rRNA gene identity, 98.3 %). However, genome-based phylogenetic analysis of strain AMP^T reveals that this bacterium is in fact a novel species of the genus Moorella. Genome relatedness indices between strain AMP^T and Moorella thermoacetica DSM 521^T were below the minimum threshold values required to consider them members of the same species (digital DNA-DNA hybridization, 52.2 % (<70%); average nucleotide identity, 93.2 % (<95%)). Based on phylogenetic and phenotypic results we recommend that strain AMP^T (DSM 21394^T=JCM 35360^T) should be classified as representing new species, for which we propose the name Moorella caeni sp. nov.