Gemmobacter lanyuensis sp. nov., isolated from a freshwater spring.

A bacterial strain designated Orc-4(T) was isolated from a freshwater spring in Taiwan and characterized using the polyphasic taxonomic approach. Cells of strain Orc-4(T) were facultatively anaerobic, Gram-reaction-negative, poly-β-hydroxybutyrate-accumulating, non-motile rods surrounded by a thick capsule and forming cream-white colonies. Growth occurred at 15-40 °C (optimum, 25-30 °C), at pH 6.0-9.0 (optimum, pH 7.0) and with 0-1 % NaCl (optimum, 0-0.5 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Orc-4(T) belonged to the genus Gemmobacter within the family Rhodobacteraceae of the class Alphaproteobacteria and its most closely related neighbour was Gemmobacter fontiphilus JS43(T) with sequence similarity of 97.8 %. Strain Orc-4(T) contained C18 : 1ω7c as the predominant fatty acid. The major respiratory quinone was Q-10. The DNA G+C content of the genomic DNA was 63.5 mol%. The polar lipid profile consisted of a mixture of phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one uncharacterized aminolipid and several uncharacterized phospholipids. The DNA-DNA relatedness of strain Orc-4(T) with respect to recognized species of the genus Gemmobacter was less than 48 %. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain Orc-4(T) represents a novel species of the genus Gemmobacter, for which the name Gemmobacter lanyuensis sp. nov. is proposed. The type strain is Orc-4(T) ( = BCRC 80378(T) = LMG 26667(T) = KCTC 23714(T)).