Aminithiophilus ramosus gen. nov., sp. nov., a sulphur-reducing bacterium isolated from a pyrite-forming enrichment culture, and taxonomic revision of the family Synergistaceae

Nathalie Pradel (1) , Marie-Laure Fardeau (2, 1) , Boyke Bunk (3) , Cathrin Spröer (3) , Christian Boedeker (3) , Jacqueline Wolf (3) , Meina Neumann-Schaal (3) , Michael Pester (3) , Stefan Spring (3)

1 MIO - Institut méditerranéen d'océanologie
2 AMU - Aix Marseille Université
3 DSMZ - Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH / Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures

A novel sulphur-reducing bacterium was isolated from a pyrite-forming enrichment culture inoculated with sewage sludge from a wastewater treatment plant. Based on phylogenetic data, strain J.5.4.2-T.3.5.2 T could be affiliated with the phylum Synergistota . Among type strains of species with validly published names, the highest 16S rRNA gene sequence identity value was found with Aminiphilus circumscriptus ILE-2 T (89.2 %). Cells of the new isolate were Gram-negative, non-spore-forming, straight to slightly curved rods with tapered ends. Motility was conferred by lateral flagella. True branching of cells was frequently observed. The strain had a strictly anaerobic, asaccharolytic, fermentative metabolism with peptides and amino acids as preferred substrates. Sulphur was required as an external electron acceptor during fermentative growth and was reduced to sulphide, whereas it was dispensable during syntrophic growth with a Methanospirillum species. Major fermentation products were acetate and propionate. The cellular fatty acid composition was dominated by unsaturated and branched fatty acids, especially iso-C 15 : 0 . Its major polar lipids were phosphatidylglycerol, phosphatidylethanolamine and distinct unidentified polar lipids. Respiratory lipoquinones were not detected. Based on the obtained data we propose the novel species and genus Aminithiophilus ramosus , represented by the type strain J.5.4.2-T.3.5.2 T (=DSM 107166 T =NBRC 114655 T ) and the novel family Aminithiophilaceae fam. nov. to accommodate the genus Aminithiophilus . In addition, we suggest reclassifying certain members of the Synergistaceae into new families to comply with current standards for the classification of higher taxa. Based on phylogenomic data, the novel families Acetomicrobiacea e fam. nov., Aminiphilaceae fam. nov., Aminobacteriaceae fam. nov., Dethiosulfovibrionaceae fam. nov. and Thermovirgaceae fam. nov. are proposed.

Domaines: Sciences de l'environnement

Nathalie Pradel, Marie-Laure Fardeau, Boyke Bunk, Cathrin Spröer, Christian Boedeker, et al.. Aminithiophilus ramosus gen. nov., sp. nov., a sulphur-reducing bacterium isolated from a pyrite-forming enrichment culture, and taxonomic revision of the family Synergistaceae. International Journal of Systematic and Evolutionary Microbiology, 2023, 73 (2), ⟨10.1099/ijsem.0.005691⟩. ⟨hal-04455059⟩