Description and genome analysis of Aoguangibacterium sediminis gen. nov., sp. nov., a noval denitrifying and carbon-fixing bacterium isolated from marine sediment

Abstract A Gram-stain-negative, non-motile, aerobic, red colony, mesophilic, and slightly halotolerant bacteria with carbon fixation and denitrification, designated strain D16T, was separated from intertidal surface sediments from Xiaoshi Island, Weihai, China. The strain was able to grow at 10–43°C, pH 5.5–9.5 and in 0–5% (w/v) NaCl. Optimum growth conditions of the strain were at pH 7.0, 30–33°C and 1% (w/v) NaCl. The predominant respiratory quinone, major fatty acids and polar lipids of the strain were (MK-6), (iso-C15:0, 32.0%, C16:0, 10.5%) and (DPG、PE、AGL、 GL、 AL、PGS), respectively. Phylogenetic analysis based on 16S rRNA gene sequences and genomes indicated that strain D16T was the closest to genera Eudoraea, Poritiphilus, Muriicola, Robiginitalea and Zeaxanthinibacter, sharing 92–93% 16S rRNA gene sequence similarity with the representative of these genera. The draft genome of strain D16T composed 3,225,638 bp, and the G + C content was 42.8 mol %. The ANI, dDDH, AAI values of strain D16T compared to similar genera ranged from 67.3 to 70.2%, 16.2 to 19.1% and 68.3 to 70.1%, respectively, below the threshold for recommended species division of ANI 95–96%, dDDH 70% and AAI 95%. Furthermore, POCP values between strain D16T and similar genera were less than 50.0%, consistent with the description of a new genus. Based on the results of phylogenetic, phenotypic, genotypic, chemotaxonomic analyses and comparative analysis of metabolic pathway, environmental distribution and characterization between in strain D16T and other relative genera of family Flavobacteriaceae, it is concluded that strain D16T represents a novel species of a noval genus of the family Flavobacteriaceae, for which the name Aoguangibacterium sediminis gen.nov., sp. is proposed. The type strain is D16T (= MCCC 1H00463T = KCTC 82746T).