Chelativorans intermedius sp. nov. and proposal to reclassify Thermovum composti as Chelativorans composti comb. nov.

Abstract

Two Gram-stain-negative, non-endospore-forming, rod-shaped bacteria, strains CC-MHSW-5T and A1392, were isolated from water of coastal hot springs located in Taiwan and China, respectively, and investigated for their taxonomic position. The two strains shared identical 16S rRNA gene sequences, a DNA-DNA hybridization value >80 % and similar genomic DNA G+C contents (64.3 and 64.6 mol%), but showed different genomic fingerprint patterns generated by BOX-PCR and three random amplification polymorphic DNA PCRs. The strains shared highest 16S rRNA gene sequence similarities with the type strains of Chelativorans multitrophicus (96.7 and 96.1 %), Thermovum composti (96.2 and 96.1 %) and Chelativorans oligotrophicus (96.1 and 95.8 %). Phylogenetic trees (based on 16S rRNA and recA gene sequence comparisons) showed a distinct clustering of both strains with the type strains of species of the genus Chelativorans and T. composti Nis3T. The quinone systems of strains CC-MHSW-5T and Nis3T contained ubiquinone Q-10 as the major component. The major polyamine in both strains was sym-homospermidine. Putrescine, spermidine and, for strain CC-MHSW-5T, spermine were found in minor concentrations. Their polar lipid profiles consisted of phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and diphosphatidylglycerol. The fatty acid profile contained major amounts of C18 : 1ω7c and C19 : 0 cyclo ω8c. On the basis of these results, the two strains are considered to represent a novel species of the genus Chelativorans , for which the name Chelativorans intermedius sp. nov. is proposed. The type strain is CC-MHSW-5T ( = CCM 8543T = LMG 28482T = DSM 29391T = CIP 110825T). Based on both genotypic and phenotypic characters, it is proposed that T. composti be reclassified within the genus Chelativorans as Chelativorans composti comb. nov.