Keguizhuia sedimenti gen. nov., sp. nov., isolated from river sediment represents a novel genus of the family Oxalobacteraceae.

Abstract

A Gram-stain-negative bacterium, designated as R-40T, was isolated from sediment of the Mulong river in Mianyang city, Sichuan province, PR China. The cells of strain R-40T were aerobic non-motile and formed translucent white colonies on R2A agar. Growth occurred at 15-37 °C (optimum 30 °C), pH 5.0-9.0 (optimum 7.0) and salinities of 0-3.0 % (w/v, optimum 0 %). R-40T showed 95.2-96.6 % 16S rRNA gene sequence similarities with the type strains of species of the genera Oxalicibacterium, Herminiimonas, Lacisediminimonas, Paucimonas, Herbaspirillum and Noviherbaspirillum in the family Oxalobacteraceae. The results of phylogenetic analysis based on genome sequences indicated that the strain was clustered with type strains of species of the genera Oxalicibacterium and Herminiimonas in the family Oxalobacteraceae but formed a distinct lineage. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH) and average amino acid identity (AAI) values between R-40T and type strains of species of the genera Oxalicibacterium, Herminiimonas, Lacisediminimonas, Paucimonas, Herbaspirillum and Noviherbaspirillum ranged from 69.3 to 74.1 %, from 18.2 to 21.4 % and from 60.1 to 67.4 %, respectively. The major cellular fatty acids were C16 : 0, C17 : 0 cyclo and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The major quinone was ubiquinone-8 (Q-8). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phospholipid and small amounts of glycophospholipids. The genome size of R-40T was 5.1 Mbp with 54.0 % DNA G+C content. On the basis of the evidence presented in this study, strain R-40T represents a novel species of a novel genus in the family Oxalobacteraceae, for which the name Keguizhuia sedimenti gen. nov., sp. nov. (type strain R-40T=MCCC 1K08818T=KCTC 8137T) is proposed.