ISOLATION AND CHARACTERIZATION OF METHANOBREVIBACTER-ORALIS SP-NOV

A new coccobacillary, nonmotile, Gram-positive, methane-producing orga nism was isolated from human subgingival plaque. Both hydrogen and car bon dioxide were required for growth. No methane was produced from ace tate, formate, or methanol. The optimum pH was 6.9-7.4, and the optimu m temperature was 36-38 degrees C. Fecal extract was required for grow th, and a volatile fatty acid mixture was highly stimulatory. The DNA G+C content was 28 mol%. On the basis of these characteristics, DNA-DN A hybridization studies, and electrophoretic analysis of cellular prot eins, the isolate was considered a new species and named Methanobrevib acter oralis.