Actinomadura amylolytica sp. nov. and Actinomadura cellulosilytica sp. nov., isolated from geothermally heated soil

Two aerobic, Gram-positive actinomycetes, designated YIM 77502T and YIM 77510T, were isolated from geothermally heated soil of Tengchong county, Yunnan province, south-west China. The taxonomic position of strains YIM 77502T and YIM 77510T were investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains YIM 77502T and YIM 77510T belong to the genus Actinomadura. Both strains form extensively-branched substrate and aerial mycelia which differentiated into short spore chains. The cell wall of the two strains contained meso-diaminopimelic acid, while the whole-cell sugars detected were glucose, madurose, mannose and rhamnose. The polar lipid profile of strain YIM 77502T was found to consist of diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol, two unidentified phospholipids and an unidentified polar lipid, while strain YIM 77510T consisted of diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. The respiratory quinones of strains YIM 77502T and YIM 77510T were MK-9(H6) and MK-9(H8). The major fatty acids (>10 %) of strain YIM 77502T were C17:0, iso-C16:0, C17:010-methyl and iso-C18:0, and those of strain YIM 77510T were iso-C16:0, C17:010-methyl and iso-C18:0. The G+C contents of strains YIM 77502T and YIM 77510T were determined to be 71.3 and 70.2 mol%, respectively. The DNA–DNA hybridization values of strains YIM 77502T, YIM 77510T and their closest phylogenetic neighbours Actinomadura echinospora BCRC 12547T and Actinomadura umbrina KCTC 9343T were less than 70 %. Based on the morphological and physiological properties, and phylogenetic analyses, strains YIM 77502T and YIM 77510T are considered to represent two novel species of the genus Actinomadura, for which the names Actinomadura amylolytica sp. nov. (type strain YIM 77502T = DSM 45822T = CCTCC AA 2012024T) and Actinomadura cellulosilytica sp. nov. (type strain YIM 77510T = DSM 45823T = CCTCC AA 2012023T) are proposed.