Rhodococcus electrodiphilus sp. Nov., a marine electro active actinobacterium isolated from coral reef

Abstract

An electrogenic bacterium was isolated from a marine coral, designated as strain JC435T and its taxonomic status examined by using a polyphasic approach. Results from the 16S rRNA gene sequence study showed that the isolate belonged to the genus Rhodococcus and formed a cluster with Rhodococcus ruber KCTC 9806T (99.5 % 16S rRNA gene sequence similarity) and Rhodococcus aetherivorans JCM 14343T (99.3 %), respectively. Genome relatedness based on DNA–DNA hybridization to the type strains of closest-related species was less than 30 % and the DTm of > 7° C, suggesting that strain represents a new species of the genus Rhodococcus. The major fatty acids were C16:0, C18:1 ω9c, C18:010-methyl and C16:1ω6c and/or C16:1 ω7c. The polar lipids of strain JC435T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside, phosphatidylinositol, three unknown phospholipids and an unknown amino lipid. The major isoprenoid quinone was MK-8(H2), with 8 % of MK-7(H2) and 2 % of MK-9(H2) as minor components. Whole-cell hydrolysates contained meso-diaminopimelic acid, arabinose and galactose as the diagnostic diamino acid and sugars. Mycolic acids were detected. The genomic DNA G+C content of strain JC435T was 69.8 mol%. On the basis of phylogenetic genotypic, physiological and chemotaxonomic analysis, strain JC435T is considered to represent a novel species of the genus Rhodococcus for which the name Rhodococcus electrodiphilus sp. nov. is proposed. The type strain is JC435T (=KCTC 39856T =LMG 29881T =MCC 3659T).