Influence of Iron Oxides on Methanogenic Process of Organic Matter and Related~Mechanism
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摘要: 甲烷 (CH4)不仅是自然界产生的重要温室气体,也是人类已经推广利用的可再生能源之一. 作为自然界广泛存在的矿物,铁氧化物同厌氧微生物的交互作用对产甲烷过程具有显著的影响. 主要针对不同铁氧化物-厌氧微生物体系内的产甲烷效率,铁氧化物及微生物群落演化,铁氧化物的作用机制等进行总结分析. 铁氧化物在微生物的作用下会发生溶解、还原并可能产生新的矿物. 而铁氧化物的直接和间接影响微生物群组成,进而影响产甲烷过程,主要体现在4个方面:(1) 铁氧化物溶解及生物还原产生的Fe3+/Fe2+影响微生物活性和体系氧化还原电位;(2) 铁还原菌和产甲烷菌竞争产甲烷基质;(3) 铁氧化物对产甲烷菌的直接抑制毒性;(4) 具有导电性能的铁氧化物可以作为电子传递媒介促进铁还原菌或脂肪酸氧化菌与产甲烷菌之间的直接电子传递过程. 最后,探讨了铁氧化物促进产甲烷过程尚需解决的主要问题及研究趋势,以期推动铁氧化物-厌氧微生物交互作用及其环境效应方面的研究工作.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
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Key words:
- iron oxides /
- anaerobic microorganism /
- electron transfer /
- methane
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