Sanae SAKAI

Cultivation of uncultivated methanogens by using anaerobic, syntrophic substrate-degrading cultures.

Akiyoshi OHASHI, Hideki HARADA, Hiroyuki IMACHI


In order to isolate uncultivated methanogens, 10 kinds of environmental samples were cultivated by using anaerobic, syntrophic substrate-degrading culture which is a novel method for cultivation of methanogen. While same samples were cultivated by the general cultivation methods for methanogens, as a control.

By using general methods, methanoegs only belonged to the order Methanobacteriales which was well-known methanoegenic group were cultivated. While, cultivation by the novel method, uncultured methanogen was cultivated. This methanogen were affiliated with the group 'Rice Cluster I' which is the one of the as-yet uncultured methanogenic group belongs to the class Methanomicrobia.

To isolate these novel methanogens, H2/CO2 and formate (a substrate for most methanogens) were used as the sole energy source. After several attempts to purify the microbes, we successfully isolate novel methanogen, designated strain SANAE.

These results suggested that the novel methods, cultivation of methogens by using anaerobic, syntrophic substrate-degrading cultures could be one of the effective methods for cultivated uncultured methanogens.