Garcia-Robledo Emilio, Ottosen Lars D M, Voigt Niels V, Kofoed M W, Revsbech Niels P
Section of Microbiology, Department of Bioscience, Aarhus University Aarhus, Denmark.
Biological and Chemical Engineering, Department of Engineering, Aarhus University Aarhus, Denmark.
Front Microbiol. 2016 Aug 17;7:1276. doi: 10.3389/fmicb.2016.01276. eCollection 2016.
Biogas production is a key factor in a sustainable energy supply. It is possible to get biogas with very high methane content if the biogas reactors are supplied with exogenous hydrogen, and one of the technologies for supplying hydrogen is through gas permeable membranes. In this study the activity and stratification of hydrogen consumption above such a membrane was investigated by use of microsensors for hydrogen and pH. A hydrogenotrophic methanogenic community that was able to consume the hydrogen flux within 0.5 mm of the membrane with specific rates of up to 30 m(3) H2 m(-3) day(-1) developed within 3 days in fresh manure and was already established at time zero when analyzing slurry from a biogas plant. The hydrogen consumption was dependent on a simultaneous carbon dioxide supply and was inhibited when carbon dioxide depletion elevated the pH to 9.2. The activity was only partially restored when the carbon dioxide supply was resumed. Bioreactors supplied with hydrogen gas should thus be carefully monitored and either have the hydrogen supply disrupted or be supplemented with carbon dioxide when the pH rises to values about 9.
沼气生产是可持续能源供应的关键因素。如果向沼气反应器供应外源氢，就有可能获得甲烷含量很高的沼气，而供应氢的技术之一是通过气体渗透膜。在本研究中，通过使用氢和pH微传感器研究了这种膜上方氢消耗的活性和分层情况。在新鲜粪便中，一个能够在膜的0.5毫米范围内以高达30立方米氢气每立方米每天的特定速率消耗氢通量的氢营养型产甲烷群落，在3天内形成，并且在分析沼气厂的淤浆时，在零时就已经存在。氢的消耗取决于同时供应二氧化碳，当二氧化碳耗尽使pH值升高到9.2时，氢消耗受到抑制。当恢复二氧化碳供应时，活性仅部分恢复。因此，供应氢气的生物反应器应仔细监测，当pH值上升到约9时，要么中断氢气供应，要么补充二氧化碳。
