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bioRxiv · 10.64898/2026.08.23.746564

Peptonella octanoica gen. nov., sp. nov., a new medium-chain carboxylate-producing bacterium, and the reclassification of Eubacterium pyruvativorans as Peptonella pyruvativorans comb. nov.

Kumar Nallasamy, D.·Lindner, B. G.·Lawson, C. E.
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Abstract

A strictly anaerobic bacterial strain, F2T, was isolated from an anaerobic bioreactor fermenting source-separated organic waste. Cells of strain F2T are non-spore-forming, rod-shaped (1.5-2.5 x 0.27-0.33 m), and Gram-negative, although they possess a monoderm cell wall architecture. The strain grew at 37 degrees C within a pH range of 5 to 8 and produced short-, branched-, and medium-chain carboxylates as well as ammonium, H2 and CO2, with acetate and propanoate produced or consumed depending on fermentation conditions. The genome consists of a single 2.4 Mbp chromosome with a G+C content of 50.2% and 2,131 predicted genes. Phylogenetic analysis of the 16S rRNA gene against other isolates revealed that strain F2T is most similar to Eubacterium pyruvativorans I-6T (92.06% 16S rRNA identity). Based on further phenotypic, genomic, and phylogenetic analysis, strain F2T represents a novel genus and species within the family Anaerovoracaceae with the proposed name Peptonella octanoica gen. nov. sp. nov. The type strain is F2T (strain accession pending). As a member of this same genus-level clade, we propose reclassifying Eubacterium pyruvativorans as Peptonella pyruvativorans comb. nov. These findings disambiguate Peptonella spp. from the phylogenetically distant and phenotypically distinct Eubacterium limosum ATCC 8486T.

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Kumar Nallasamy, D., Lindner, B. G., Lawson, C. E.. 2026-08-24. Peptonella octanoica gen. nov., sp. nov., a new medium-chain carboxylate-producing bacterium, and the reclassification of Eubacterium pyruvativorans as Peptonella pyruvativorans comb. nov.. https://doi.org/10.64898/2026.08.23.746564

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