Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Microorganisms 2794 [13 ] archaea methanogens human gut microbiota Methanomassiliicoccales 2023 fdi:010088750 ENG Microorganisms ISI:001114702200001 11 10.3390/microorganisms11112794 https://www.documentation.ird.fr/hor/fdi:010088750 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2024-01/010088750.pdf 11 Horizon (IRD) The methanogenic strain Mx-05(T) was isolated from the human fecal microbiome. A phylogenetic analysis based on the 16S rRNA gene and protein marker genes indicated that the strain is affiliated with the order Methanomassiliicoccales. It shares 86.9% 16S rRNA gene sequence identity with Methanomassiliicoccus luminyensis, the only member of this order previously isolated. The cells of Mx-05(T) were non-motile cocci, with a diameter range of 0.4-0.7 mu m. They grew anaerobically and reduced methanol, monomethylamine, dimethylamine, and trimethylamine into methane, using H-2 as an electron donor. H-2/CO2, formate, ethanol, and acetate were not used as energy sources. The growth of Mx-05(T) required an unknown medium factor(s) provided by Eggerthella lenta and present in rumen fluid. Mx-05(T) grew between 30 degrees C and 40 degrees C (optimum 37 degrees C), over a pH range of 6.9-8.3 (optimum pH 7.5), and between 0.02 and 0.34 mol.L-1 NaCl (optimum 0.12 mol.L-1 NaCl). The genome is 1.67 Mbp with a G+C content of 55.5 mol%. Genome sequence annotation confirmed the absence of the methyl branch of the H4MPT Wood-Ljungdahl pathway, as described for other Methanomassiliicoccales members. Based on an average nucleotide identity analysis, we propose strain Mx-05(T) as being a novel representative of the order Methanomassiliicoccales, within the novel family Methanomethylophilaceae, for which the name Methanomethylophilus alvi gen. nov, sp. nov. is proposed. The type strain is Mx-05(T) (JCM 31474T). 084 ; 054 ; 020 UR235