Smaragdicoccus niigatensis gen. nov., sp. nov., a novel member of the suborder Corynebacterineae

Abstract

A polyphasic taxonomic approach was applied to determine the taxonomic position of a hydrocarbon-degrading actinomycete, strain Hou_blueT, which was isolated from soil samples collected from an oil spring in Niigata, Japan. The results of 16S rRNA and gyrB gene sequence comparisons indicated that strain Hou_blueT represented a novel lineage in the suborder Corynebacterineae. Colonies were malachite green-like in colour on 1/10 trypticase soy agar and the cell morphology was coccoid in all growth phases. The cell-wall diamino acid and sugar indicated chemotype IV and variation A1γ. The sugars of the peptidoglycan were glycolated. The polar lipids were composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and some unspecified glycolipids. The organism contained two novel cyclic forms of menaquinone, smaragdiquinone A-8(H4, ω-cycl) and smaragdiquinone B-8(H4, dicycl). The major fatty acids were cis-9-18 : 1 (34.46 %) and 16 : 0 (25.1 %). Small amounts of 10-methyl-branched fatty acids were also present (10-methyl-17 : 0, 0.17 %), but not tuberculostearic acid (10-methyl-18 : 0), which has been shown to be present in all nocardiae. Gas-chromatographic analysis of the mycolic acid revealed a carbon-chain length of C43–C49. The DNA G+C content was 63.7 mol%. On the basis of phenotypic and phylogenetic distinctness, the organism is proposed to represent a novel genus and species, Smaragdicoccus niigatensis gen. nov., sp. nov., with the type strain Hou_blueT (=MBIC 06267T=DSM 44881T).