f Isolation and Characterization of Methanogenium bourgense sp. nov.

Methane-producing bacterial strain MS2T(T = type strain) was isolated from a tannery by-products enrichment culture inoculated with sewage sludge. This methanogen was a non-motile, irregular coccoid organism (diameter, 1 to 2 μm) which used H2-CO2 and formate as methanogenic substrates. Acetate was required for growth but did not serve as a methanogenic substrate; yeast extract and Trypticase peptone were highly stimulatory. Growth occurred through the pH range from 5.5 to 8.0, with optimum growth at pH 6.7. The optimum temperature for growth was 37°C. The deoxyribonucleic acid base composition was 59 mol% guanine plus cytosine. The physiological and antigenic properties of this isolate place it in the genus Methanogenium. The organism is named Methanogenium bourgense sp. nov.