Thermoaminiphila catenidiffluenda gen. nov., sp. nov.: A novel thermophilic, strictly anaerobic bacterium representing Thermoaminiphilia class nov., a newly described class thriving in hydrocarbon-rich habitats and biogas fermenters

Axenic cultivation of novel bacterial lineages, referred to as “gold standard in microbiology”, remains challenging for fastidious or uncultured taxa due the challenges of replicating adequate growth conditions. We isolated strain PM69, a representative of the previously undescribed Bacillota class SHA-98, from a phenyl acid degrading, oligotrophic batch culture. By employing a broad spectrum of (anaerobic) culture techniques, biochemical, physiological, and genomic analyses, we characterised the strain as Thermoaminiphila catenidiffluenda , gen. nov., sp. nov., a thermophilic, strictly anaerobic, bacterium fermenting monosaccharides to acetate. Its motility, biofilm forming capacity, and ecological niche in biogas fermenters and hydrocarbon-associated habitats suggest adaptive strategies for harsh environments exhibiting e.g., high concentrations of aromatic compounds. This description of a new bacterial class not only expands the taxonomic diversity of phylum Bacillota but also provides insights into the metabolic versatility of yet uncultured microorganisms, with implications for carbon cycling and biotechnological applications.