Improved technique for identification and enumeration of methanogenic bacterial colonies on roll tubes by epifluorescence microscopy.

Methanogenic fluorescent colonies can be clearly identified on roll tubes by using an epifluorescence microscope equipped with a x 2 objective. Methanogenic and nonmethanogenic colonies could be counted in roll tubes prepared from methanogenic enrichment cultures. Late-developing colonies appearing after 25 days of incubation were mainly methanogenic.