Chryseomicrobium excrementi sp. nov., a Gram-stain-positive rod-shaped bacterium isolated from an earthworm (Eisenia fetida) cast

Abstract

A Gram-stain-positive, rod-shaped, slightly halotolerant, nitrate-reducing bacterial strain, designated ET03T, was isolated from the cast of an earthworm (Eisenia fetida) reared at the Centre of Floriculture and Agribusiness Management, University of North Bengal at Siliguri, West Bengal, India. On the basis of 16S rRNA gene sequence phylogeny, the closest relative of strain ET03T was Chryseomicrobium palamuruense PU1T (99.1 % similarity). The DNA G+C content of strain ET03T was 42.9 mol%. Strain ET03T contained menaquinone-8 as the most predominant menaquinone and phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and phosphatidylglycerol as the main polar lipids. The diagnostic diamino acid was meso-diaminopimelic acid. Major cellular fatty acids were iso-C15 : 0, C16 : 1ω7c alcohol and iso-C16 : 0. Other biochemical and physiological analyses supported genotypic and phenotypic differentiation of the strain ET03T from its nearest taxonomic neighbours: Chryseomicrobium palamuruense, Chryseomicrobium amylolyticum , Chryseomicrobium imtechense , Chryseomicrobium aureum and Chryseomicrobium deserti. The draft genome of strain ET03T consisted of 2.64 Mb distributed in 14 scaffolds (N50 894072). A total of 2728 genes were predicted and, of those, 2664 were protein-coding genes including genes involved in the degradation of polychlorinated biphenyl and several aromatic compounds. The isolate, therefore, represents a novel species, for which the name Chryseomicrobium excrementi sp. nov. is proposed. The type strain is ET03T (=KCTC 33943T=LMG 30119T=JCM