Reclassification of Promicromonospora pachnodae Cazemier et al. 2004 as Xylanimicrobium pachnodae gen. nov., comb. nov.

The recently described facultatively anaerobic Promicromonospora pachnodae is phylogenetically only moderately related to authentic members of Promicromonospora. P. pachnodae is closely related to Xylanibacterium ulmi and slightly less closely related to Xylanimonas cellulosilytica and Isoptericola variabilis (basonym Cellulosimicrobium variabile). Members of the different genera of Promicromonosporaceae have similar chemotaxonomic properties; they share the same peptidoglycan type (A4alpha) and have similar profiles of polar lipids, menaquinones, fatty acids and whole cell sugars. However, they differ from each other in the detailed amino acid composition of peptidoglycan, a taxonomically significant character that has previously been used in the delineation of actinobacterial genera. Recognized Promicromonospora species and Xylanibacterium ulmi exhibit the L-Lys-L-Ala-D-Glu type, Xylanimonas cellulosilytica and I. variabilis show the L-Lys-D-Asp type, whereas P. pachnodae has the L-Lys-L-Ser-D-Glu type. This property, together with the distinct phylogenetic position of Promicromonospora pachnodae, suggests a novel genus for the xylanolytic organism Xylanimicrobium pachnodae (Cazemier et al. 2004) gen. nov., comb. nov.