Description of Paenisporosarcina quisquiliarum gen. nov., sp. nov., and reclassification of Sporosarcina macmurdoensis Reddy et al. 2003 as Paenisporosarcina macmurdoensis comb. nov.

In the course of a study of the prokaryotic diversity of a landfill site in Chandigarh, India, a strain designated SK 55(T) was isolated and characterized using a polyphasic approach. Its 16S rRNA gene sequence showed closest similarity (98.3 %) to that of Sporosarcina macmurdoensis CMS 21w(T). The sequence similarity to strains of other hitherto described species of Sporosarcina was less than 95.5 %. Strain SK 55(T) contains peptidoglycan of the A4alpha type (l-Lys-d-Asp), MK-8 and MK-7 as the major menaquinones and iso-C(15 : 0) as the major fatty acid. Strain SK 55(T), Sporosarcina macmurdoensis and Sporosarcina ureae, the type species of the genus, had some polar lipids in common (diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, a phospholipid and an unknown lipid). However, an aminolipid, an aminophospholipid and an unknown lipid found in the former two organisms are similar, though not identical, but quite different from the profile of S. ureae. The genomic DNA G+C contents of strain SK 55(T) (46.0 mol%) and S. macmurdoensis CMS 21w(T) (44.0 mol%) are higher than those reported for the majority of species of Sporosarcina (36-42 mol%). As revealed by 16S rRNA gene sequence analysis, strain SK 55(T) and S. macmurdoensis CMS 21w(T) form a clade which is distinct from the clade occupied by other species of Sporosarcina. On the basis of phenotypic characteristics including chemotaxonomic data and analysis of the 16S rRNA gene sequence, we conclude that strain SK 55(T) should be considered as a member of a novel genus and species, for which the name Paenisporosarcina quisquiliarum gen. nov., sp. nov. is proposed. The type strain of Paenisporosarcina quisquiliarum is SK 55(T) (=MTCC7604(T) =JCM 14041(T)). S. macmurdoensis CMS 21w(T) shows more similarity in its 16S rRNA gene sequence (98.3 %), DNA G+C content and polar lipid profile to strain SK 55(T) than to S. ureae DSM 2281(T). Phylogenetically, it forms a coherent cluster with strain SK 55(T) which is separate from the Sporosarcina cluster. Moreover, iso-C(15 : 0), anteiso-C(15 : 0) and C(16 : 1)omega7c alcohol are the three major fatty acids in both S. macmurdoensis CMS 21w(T) and SK 55(T). All these data suggest that S. macmurdoensis should be a member of the genus Paenisporosarcina. However, S. macmurdoensis can be differentiated from SK 55(T) in several physiological and biochemical characteristics, especially in the patterns of oxidation and acid production from carbohydrates. The genomic relatedness of S. macmurdoensis CMS 21w(T) and strain SK 55(T) was also very low (18.0 %). It is therefore logical to transfer Sporosarcina macmurdoensis to the newly created genus as Paenisporosarcina macmurdoensis comb. nov. The type strain is CMS 21w(T) (=MTCC4670(T) =DSM 15428(T)).