Aquincola rivuli sp. nov., isolated from a freshwater stream.

Abstract

Strain KYPY4T, isolated from a water sample taken from the Funglin stream in Taiwan, was characterized using a polyphasic taxonomic approach. The 16S rRNA gene sequence of strain KYPY4T was closely related to Ideonella dechloratans CCUG 30898T (97.1 %) followed by Aquincola tertiaricarbonis L10T (96.9 %) and Kinneretia asaccharophila KIN192T (96.8 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain KYPY4T belonged to the genus Aquincola and formed a distinct phyletic line with A. tertiaricarbonis L10T and Aquincola amnicola TTM-94T. The draft genome of strain KYPY4T was approximately 4.93 Mb in size with a G+C content of 70.1 mol%. Strain KYPY4T showed 73.4-76.9 % average nucleotide identity and 21.3-22.5 % digital DNA-DNA hybridization identity with the strains of other related species in the Rubrivivax-Roseateles-Leptothrix-Ideonella-Aquabacterium group. Cells of strain KYPY4T were Gram-stain-negative, aerobic, motile, surrounded by a thick capsule and formed light orange colonies. Optimal growth occurred at 30 °C, pH 7 and 0 % NaCl. Strain KYPY4T contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 1ω7c as the predominant fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and several uncharacterized polar lipids. The major respiratory quinone was Q-8. On the basis of phenotypic and genotypic properties and phylogenetic inference, strain KYPY4T should be classified as a novel species of the genus Aquincola, for which the name Aquincola rivuli sp. nov. is proposed. The type strain is KYPY4T (=BCRC 81010T=KCTC 52441T).