Mucilaginibacter celer sp. nov. and Aquirhabdus parva gen. nov., sp. nov., isolated from freshwater

Abstract

Two novel bacteria, designated HYN0043T and HYN0046T, were isolated from a freshwater lake in Korea. 16S rRNA gene sequence phylogeny indicated that strain HYN0043T belongs to the genus Mucilaginibacter of the family Sphingobacteriaceae because it showed highest sequence similarity to Mucilaginibacter oryzae (98.2 %). The average nucleotide identity between strain HYN0043T and M. oryzae was 83.5 %, which is clearly below the suggested threshold for species demarcation. Strain HYN0046T was found to belong to the family Moraxellaceae and shared highest sequence similarity with Agitococcus lubricus (93.8 %). The average amino acid identity values between strain HYN0046T and representative type strains of closely related genera (Alkanindiges, Agitococcus and Acinetobacter ) were 53.1–60.7 %, implying the novelty of the isolate at the genus level. Phenotypic characteristics (physiological, biochemical and chemotaxonomic) also supported the taxonomic novelty of the two isolates. Thus, we suggest the following names to accommodate strains HYN0043T and HYN0046T: Mucilaginibacter celer sp. nov. (type strain HYN0043T=KACC 19184T=NBRC 112738T) in the family Spingobacteriaceae and phylum Bacteroidetes and Aquirhabdus parva gen. nov., sp. nov. (type strain HYN0046T=KACC 19178T=NBRC 112739T) in the family Moraxellaceae and phylum Proteobacteria .