Three actinomycetes (strains HKI 0478 T , HKI 0479 and HKI 0480) isolated from the surfaces of rocks in the Feengrotten medieval alum slate mine (Thuringia, Germany) were examined in a polyphasic taxonomic study. The following morphological and chemotaxonomic features supported their classification as members of the genus Kribbella: the presence of LLdiaminopimelic acid in the cell-wall peptidoglycan; glucose together with minor amounts of mannose and ribose as the whole-cell sugars; polar lipids comprising phosphatidylcholine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and unknown phospho-and glycolipids; fatty acid profiles characterized by the predominance of anteiso-C 15 : 0 , iso-C 16 : 0 and C 16 : 0 9-methyl; and the presence of MK-9(H 4 ) as the main menaquinone. The isolates had almost identical 16S rRNA gene sequences (99.9-100 %) and were most closely related to the type strains of Kribbella jejuensis (98.9 % sequence similarity), Kribbella swartbergensis and Kribbella solani (both 98.8 %). A wide range of genotypic and phenotypic markers as well as the low levels of DNA-DNA relatedness between strain HKI 0478 T and the type strains of K. jejuensis (41.3 %), K. swartbergensis (18.6 %) and K. solani (14.2 %) distinguished the novel strains from their closest phylogenetic neighbours. On the basis of these results, strain HKI 0478 T represents a novel member of the genus Kribbella, for which the name Kribbella aluminosa sp. nov. is proposed. The type strain is HKI 0478 T (5DSM 18824 T 5JCM 14599 T ). Park et al. 1999 emend. Sohn et al. 2003 is a member of the family Nocardioidaceae, which was proposed by Nesterenko et al. (1985Nesterenko et al. ( , 1990 and the description of which was emended by Rainey et al. (in Stackebrandt et al., 1997). The genus Kribbella is represented by Gram-positive or Gram-variable, nonmotile actinomycetes that form an extensively branched vegetative mycelium and aerial hyphae that fragment into short to elongated rod-like or coccoid elements. Strains of the 11 Kribbella species with validly published names share the following chemotaxonomic characteristics (Park et al., 1999;Sohn et al., 2003): the presence of LL-diaminopimelic acid in the peptidoglycan (wall chemotype I sensu Lechevalier & Lechevalier, 1970), fatty acids that consist mainly of anteiso-and iso-branched components, MK-9(H 4 ) as the main menaquinone and polar lipids comprising phosphatidylcholine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol (phospholipid pattern III sensu Lechevalier et al., 1977). A combination of these chemotaxonomic markers serves to separate the strains of the genus Kribbella from members of the other genera within the family Nocardioidaceae.
The genus KribbellaThree filamentously growing actinomycetes, strains HKI 0478 T , HKI 0479 and HKI 0480, were isolated from acidic and heavy-metal-containing rock surfaces in a small mining area behind the 'Märchendom', the third level of the Feengrotten medieval alum slate mine (Saalfeld, Thuringia,...