Myceligenerans crystallogenes sp. nov., isolated from Roman catacombs.

Three xylan-degrading actinobacterial strains were isolated from different sampling sites in the Roman catacombs of Domitilla and San Callisto. The organisms showed morphological and chemotaxonomic properties such as peptidoglycan type A4alpha, L-lys-L-thr-D-Glu; whole-cell sugars (glucose, mannose and galactose); octa-, hexa- and tetrahydrogenated menaquinones with nine isoprene units; phosphatidylglycerol and diphosphatidylglycerol as the major phospholipids; anteiso-C(15 : 0), iso-C(15 : 0) and iso-C(16 : 0) as the predominant fatty acids; and a DNA G+C content of 72 mol%. These features are consistent with affiliation of these isolates to the genus Myceligenerans. The three isolates shared a 16S rRNA gene similarity of 99.9 % and were most closely related to Myceligenerans xiligouense DSM 15700T (97.9 % sequence similarity). The low level of DNA-DNA relatedness (about 14 %) and the differences in phenotypic characteristics between the novel strains and M. xiligouense DSM 15700T justify the proposal of a novel species of the genus Myceligenerans, Myceligenerans crystallogenes sp. nov., with CD12E2-27T (= HKI 0369T = DSM 17134T = NCIMB 14061T = VTT E-032285T) as the type strain.