Geodermatophilus telluris sp. nov., an actinomycete isolated from Saharan desert sand

Abstract

A novel Gram-positive, multiloculated thalli-forming, aerobic, actinobacterial strain, CF9/1/1T, was isolated in 2007 during environmental screening for xerophilic fungi in arid desert soil from the Sahara desert, Chad. The isolate grew best at a temperature range of 20–35 °C and at pH 6.0–8.5 and with 0–4 % (w/v) NaCl, forming black-coloured and irregular colonies on GYM agar. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Geodermatophilus . The DNA G+C content of the novel strain was 75.4 mol%. The peptidoglycan contained meso-diaminopimelic acid as a diagnostic diamino acid. The main phospholipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, a not yet structurally identified aminophospholipid and a small amount of phosphatidylglycerol; MK-9(H4) was identified as the dominant menaquinone and galactose was a diagnostic sugar. The major cellular fatty acids were branched-chain saturated acids: iso-C16 : 0 and iso-C15 : 0. The 16S rRNA gene sequence of the isolate showed 94.6–97.0 % sequence similarities with those of five members of the genus: Geodermatophilus ruber DSM 45317T (94.6 %), Geodermatophilus obscurus DSM 43160T (94.8 %), Geodermatophilus siccatus DSM 45419T (96.2 %), Geodermatophilus nigrescens DSM 45408T (96.7 %) and Geodermatophilus arenarius DSM 45418T (97.0 %). Based on the evidence from this polyphasic taxonomic study, a novel species, Geodermatophilus telluris sp. nov., is proposed; the type strain is CF9/1/1T ( = DSM 45421T = CCUG 62764T).