Abstract
Novel Gram-stain-negative, non-spore-forming, non-motile rods, designated HTMS2 and HTMS3(T), were isolated from a biofilm on the membrane of a municipal sewage treatment membrane bioreactor in Nagaoka, Japan. Phylogenetic analysis of 16S rRNA genes placed them in the family Burkholderiaceae, most closely related to Hydromonas duriensis A2P5 (T) (94.14% similarity). Genome sequencing (2.52 Mb, 48.2% G+C) and phylogenomic analysis affiliated them with the uncultured genus lineage CTSOIL-112 in the Genome Taxonomy Database. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values to related taxa were below species thresholds (ANI ≤77.0%, dDDH ≤54.9%). In addition, average amino acid identity values to related taxa were ≤68.6%. Both strains are catalase- and oxidase-positive, reduced nitrate and utilized various carbohydrates but not N-acetyl-glucosamine; they differed in sorbitol assimilation. The major respiratory quinone is Q-8, and the predominant fatty acids are summed feature 3 (C_16:1 ω7c/ω6c), summed feature 8 (C_18:1 ω7c/ω6c) and C_16:0. Genomic data supported a non-motile, Gram-stain-negative phenotype. Polyphasic analysis indicates that these strains represent a novel genus and species, Puribacter membranae gen. nov., sp. nov. (type strain HTMS3(T)=NBRC 117344(T)=LMG 34133(T)).