Shimazuella kribbensis gen. nov., sp. nov., a mesophilic representative of the family Thermoactinomycetaceae

Abstract

A mesophilic strain, designated A 9500T, was isolated from a soil sample collected from Sobaek Mountain, South Korea, and its taxonomic position was investigated by using a polyphasic approach. The novel strain grew well on different ISP media and no diffusible pigments were produced. The optimum temperature for growth was 32 °C. The aerial mycelium was well developed, but not fragmented. The strain was Gram-positive, non-motile and formed enclospores on vegetative and aerial hyphae with a spiny surface. Cell walls of strain A 9500T contained meso-diaminopimelic acid as the diagnostic amino acid, but no characteristic sugars or other amino acids were found (chemotype-III). The major menaquinone was MK-9(H4) and the minor menaquinone was MK-10(H4) and they were detected at a ratio of 7:3. Phosphatidylethanolamine was the diagnostic phospholipid. The G + C content of the genomic DNA was 39.4 mol%. The major fatty acids were anteiSO-C15:0 (43.34 %), iS0-C16:0 (14.23%) and C16:0 (7.90%), a composition that differed from members of related genera of the family Thermoactinomycetaceae. The novel strain formed a distinct clade in a phylogenetic tree based on 16S rRNA gene sequences. On the basis of a range of phenotypic and genotypic data and on 16S rRNA gene sequence similarities (88.35-90.38%), it is suggested that strain A 9500T represents a novel species in a new genus with the name Shimazuella kribbensis gen. nov., sp. nov. The type strain of the type species is A 9500T (=KCTC 9933T=DSM 45090T).