Reclassification of Acetomicrobium faecale as Caldicoprobacter faecalis comb. nov.

Taking into account its phenotypical and genetic characteristics, Acetomicrobium faecale was first recognized as a member of the genus Acetomicrobium, family Bacteroidaceae, order Bacteroidales, phylum Bacteroidetes, with Acetomicrobium flavidum the type species of the genus. However, it was found that A. faecale had 95.8 %, 97.6 % and 98.4 % similarity, respectively, with Caldicoprobacter guelmensis, Caldicoprobacter algeriensis and Caldicoprobacter oshimai and only 82 % similarity with A. flavidum. The DNA G+C content of A. faecale is 45 mol, which is of the same order as the DNA G+C content of the three strains of species of the genus Caldicoprobacter and its main fatty acid is C-16:0, with its second most prominent fatty acid, iso-C-17:0, also common to strains of species of the genus Caldicoprobacter. On the basis of further phylogenetic, genetic and chemotaxonomic studies, we propose that A. faecale (type strain DSM 20678(T)=JCM 30420(T)) be reclassified as Caldicoprobacter faecalis comb. nov.