Methane (CH4) is considered as the secondmost potent greenhouse
gas after carbon dioxide (CO2). It has 25 times higher global warming
potential (IPCC, 2007) over 100 year time-horizon as compared to
CO2. Approximately 1 billion tons (1 G ton) of CH4 is globally formed
per year by methanogens under anaerobic conditions (Thauer, 1998).