Abstract: Given that indigenous microbial consortia of raw coal samples are in great difficulty being separated, purificated and cultured, which are invariably at a big cost of time, biogas slurry was considered to be added as the microbial sources, of which the morphological characteristics and the amount of dominant anaerobic bacteria were determined prior to the conduction of biogenic-methane-production experiment. The results show that four types of anaerobic microbial consortia including fermentative bacteria, cellulolytic bacteria, sulfate-reducing bacteria and methanogens were separately indentified and observed with such recognizable morphological features as rod-shaped, spherical and streptobacteria; the gram-negative bacteria were found to be at a notable advantage after gram stain; further the content of microbial consortia determined by most probable number (MPN) counting method was deemed to be enough for following biogenic-methane-production experiment.

Key words: indigenous microbes, biogas slurry, biogenic methane, anaerobic microbial consortia, MPN counting