title: Ruminococcus hydrogenotrophicus sp. nov., a new H2/CO2-utilizing acetogenic bacterium isolated from human feces.
abstract: A new H2/CO2-utilizing acetogenic bacterium was isolated from the feces of a non-methane-excreting human subject. The two strains S5a33 and S5a36 were strictly anaerobic, gram-positive, non-sporulating coccobacilli. The isolates grew autotrophically by metabolizing H2/CO2 to form acetate as sole metabolite and were also able to grow heterotrophically on a variety of organic compounds. The major end product of glucose and fructose fermentation was acetate; the strains also formed ethanol, lactate and, to a lesser extent, isobutyrate and isovalerate. The G+C content of DNA of strain S5a33 was 45.2 mol%. 16S rRNA gene sequencing demonstrated that the two acetogenic isolates were phylogenetically identical and represent a new subline within Clostridium cluster XIVa. Based on phenotypic and phylogenetic considerations, a new species, Ruminococcus hydrogenotrophicus, is proposed. The type strain of R. hydrogenotrophicus is S5a33 (DSM 10507). Furthermore, H2/CO2 acetogenesis appeared to be a common property of most of the species phylogenetically closely related to strain S5a33 (Clostridium coccoides, Ruminococcus hansenii, and Ruminococcus productus).
authors.affiliation: Laboratoire de Nutrition et Sécurité Alimentaire, INRA, Domaine de Vilvert, F-78352 Jouy-en-Josas Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Bernalier
authors.forename: A
authors.initials: A
authors.lastname: Willems
authors.forename: M
authors.initials: M
authors.lastname: Leclerc
authors.forename: V
authors.initials: V
authors.lastname: Rochet
authors.forename: M D
authors.initials: MD
authors.lastname: Collins
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D001483:Base Sequence; D002245:Carbon Dioxide / Q000378:metabolism*; D005243:Feces / Q000382:microbiology*; D005285:Fermentation; D006801:Humans; D006859:Hydrogen / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D002245:Carbon Dioxide; D006859:Hydrogen