Syntrophotalea acetylenivorans sp. Nov., a diazotrophic, acetylenotrophic anaerobe isolated from intertidal sediments

Abstract

A Gram-stain-negative, strictly anaerobic, non-motile, rod-shaped bacterium, designated SFB93T, was isolated from the inter-tidal sediments of South San Francisco Bay, located near Palo Alto, CA, USA. SFB93T was capable of acetylenotrophic and diazotrophic growth, grew at 22–37 °C, pH 6.3–8.5 and in the presence of 10–45 g l−1 NaCl. Phylogenetic analyses based on 16S rRNA gene sequencing showed that SFB93T represented a member of the genus Syntrophotalea with highest 16S rRNA gene sequence similarities to Syntrophotalea acetylenica DSM 3246T (96.6 %), Syntrophotalea carbinolica DSM 2380T (96.5 %), and Syntrophotalea venetiana DSM 2394T (96.7 %). Genome sequencing revealed a genome size of 3.22 Mbp and a DNA G+C content of 53.4 %. SFB93T had low genome-wide average nucleotide identity (81–87.5 %) and <70 % digital DNA–DNA hybridization value with other members of the genus Syntrophotalea. The phylogenetic position of SFB93T within the family Syntrophotaleaceae and as a novel member of the genus Syntrophotalea was confirmed via phylogenetic reconstruction based on concatenated alignments of 92 bacterial core genes. On the basis of the results of phenotypic, genotypic and phylogenetic analyses, a novel species, Syntrophotalea acetylenivorans sp. nov., is proposed, with SFB93T (=DSM 106009T=JCM 33327T=ATCC TSD-118T) as the type strain.