Isolation and characterization of Methanocorpusculum parvum, gen. nov., spec. nov., a new tungsten requiring, coccoid methanogen

Abstract

A new mesophilic, monotrichously flagellated methane-producing coccus of ≦1μm in diameter was isolated from an anaerobic sour whey digester, originally inoculated with sewage sludge. Growth and methane production were observed with H2/CO2, formate and - less effectively - with 2-propanol/CO2. The isolate grew at temperatures between 15° C and 45° C with the optimum at around 37° C. Acetate, yeast extract and tungstate were required in the medium. Clarified rumen fluid stimulated growth. The DNA of the new methanogen has a G+C content of 48.5 mol%. Comparative 16 S rRNA oligonucleotide cataloguing allows to define the new isolate as a member of a new genus of the order Methanomicrobiales. Further evidence for this is provided by the antigenic crossreactivity with anti-S probes and by metabolic features. Because of its small size the new methanogen is named Methanocorpusculum parvum. © 1987 Springer-Verlag.