Rhodanobacter humi sp. nov., an acid-tolerant and alkalitolerant gammaproteobacterium isolated from forest soil

A novel acid-tolerant and alkalitolerant gammaproteobacterium designated strain RS22T was isolated from Kyonggi University forest soil. Cells were aerobic, Gram-stain-negative, catalase- and oxidase-positive, non-motile, non-spore-forming, rod-shaped and yellow-pigmented. Flexirubin-type pigments were absent. Strain RS22T was able to assimilate lactic acid, l-proline and 3-hydroxybenzoic acid; it tolerated 4 % (w/v) NaCl, fermented glucose and was able to grow at pH 11.0. Phylogenetic analysis based on its 16S rRNA gene sequence revealed that strain RS22T formed a lineage within the class Gammaproteobacteria of the phylum Proteobacteria that was distinct from various species of the genus Rhodanobacter, including Rhodanobacter denitrificans 2APBS1T (97.7 % sequence similarity), Rhodanobacter thiooxydans LCS2T (97.5 %), Rhodanobacter terrae GP18-1T (97.5 %) and Rhodanobacter soli DCY45T (97.2 %). The predominant respiratory quinone was Q-8. The major polar lipids of strain RS22T were phosphatidylethanolamine, phosphatidyl-N-methylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The major cellular fatty acids were summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl), iso-C15 : 0, iso-C17 : 0, iso-C16 : 0, anteiso-C15 : 0 and C16 : 0. The DNA G+C content of strain RS22T was 63.2 mol%. DNA-DNA hybridization between strain RS22T and other closest members of the genus Rhodanobacterrevealed relatedness values from 28 to 51 %. On the basis of phenotypic, genotypic, chemotaxonomic and phylogenetic analysis, strain RS22T represents a novel species of the genus Rhodanobacter, for which the name Rhodanobacter humi sp. nov. is proposed. The type strain is RS22T (=KEMB 9005-480T=KACC 19048T=NBRC 112473T).