Methanogens are essential in the formation of biogenic methane and have wide distribution in lakes, swamps,
paddy fields and ruminant rumen in the earth surface ecosystem. As a very important greenhouse gas, methane of different sources can induce global warming (Table 1).Hence, more and more attentions are paid to the population features of methanogens and formation mechanisms of biogenic methane. However, microbial
coalbed methane (CBM) has good resource prospect and exploitation potential because of the large distribution, shallow buried depth and low exploration and development cost.
