Abstract:
Methane is one of the most important greenhouse gases from nature and the renewable energy sources that human beings have explored extensively. Iron oxides, abundant mineral sources on earth, its interaction with anaerobic microorganism can exert significant influences on the methanogenic process. This review summarizes and discusses the different influences of iron oxides-anaerobic microorganism on the process of methanogenesis, including the change of iron oxides and microbial community, and the action mechanisms of iron oxides. Iron oxide could be dissolved and reduced by the microbe and novel mineral phase is generated under certain conditions. Microbial community and the function are influenced by the iron oxides which result in the change of methanogenic process. The influence could be mainly summarized as follows: (1) Fe3+/Fe2+generated from the dissolution and reduction of iron oxides influenced the microbial activity and redox potential of the surrounding environments; (2) iron reducing bacteria competed with methanogens for substrate; (3) direct toxicity of iron oxides on methanogens; (4) conductive iron oxides worked as electron conduits and promoted direct interspecies electron transfer between iron reducing bacteria syntrophic bacteria and methanogens. Finally, the research trends and main problems are proposed, which are expected to promote the studies on interaction between iron oxides and anaerobic microorganism and their environment effects