在微生物电解池中，地杆菌属物种和混合菌丛的产氢作用。
Hydrogen production by geobacter species and a mixed consortium in a microbial electrolysis cell.
机构信息
Department of Civil and Environmental Engineering, 212 Sackett Building, Penn State University, University Park, PA 16802, USA.
出版信息
Appl Environ Microbiol. 2009 Dec;75(24):7579-87. doi: 10.1128/AEM.01760-09. Epub 2009 Oct 9.
A hydrogen utilizing exoelectrogenic bacterium (Geobacter sulfurreducens) was compared to both a nonhydrogen oxidizer (Geobacter metallireducens) and a mixed consortium in order to compare the hydrogen production rates and hydrogen recoveries of pure and mixed cultures in microbial electrolysis cells (MECs). At an applied voltage of 0.7 V, both G. sulfurreducens and the mixed culture generated similar current densities (ca. 160 A/m3), resulting in hydrogen production rates of ca. 1.9 m(3) H2/m3/day, whereas G. metallireducens exhibited lower current densities and production rates of 110 +/- 7 A/m3 and 1.3 +/- 0.1 m3 H2/m3/day, respectively. Before methane was detected in the mixed-culture MEC, the mixed consortium achieved the highest overall energy recovery (relative to both electricity and substrate energy inputs) of 82% +/- 8% compared to G. sulfurreducens (77% +/- 2%) and G. metallireducens (78% +/- 5%), due to the higher coulombic efficiency of the mixed consortium. At an applied voltage of 0.4 V, methane production increased in the mixed-culture MEC and, as a result, the hydrogen recovery decreased and the overall energy recovery dropped to 38% +/- 16% compared to 80% +/- 5% for G. sulfurreducens and 76% +/- 0% for G. metallireducens. Internal hydrogen recycling was confirmed since the mixed culture generated a stable current density of 31 +/- 0 A/m3 when fed hydrogen gas, whereas G. sulfurreducens exhibited a steady decrease in current production. Community analysis suggested that G. sulfurreducens was predominant in the mixed-culture MEC (72% of clones) despite its relative absence in the mixed-culture inoculum obtained from a microbial fuel cell reactor (2% of clones). These results demonstrate that Geobacter species are capable of obtaining similar hydrogen production rates and energy recoveries as mixed cultures in an MEC and that high coulombic efficiencies in mixed culture MECs can be attributed in part to the recycling of hydrogen into current.
为了比较纯培养物和混合培养物在微生物电解池（MEC）中的产氢率和氢气回收率，将一种利用氢气的异化电化学细菌（Geobacter sulfurreducens）与一种非氢气氧化剂（Geobacter metallireducens）和混合菌进行了比较。在 0.7 V 的外加电压下，G. sulfurreducens 和混合培养物都产生了相似的电流密度（约 160 A/m3），导致产氢率约为 1.9 m3 H2/m3/day，而 G. metallireducens 的电流密度和产氢率较低，分别为 110 +/- 7 A/m3 和 1.3 +/- 0.1 m3 H2/m3/day。在混合培养物 MEC 中检测到甲烷之前，混合菌达到了最高的总能量回收率（相对于电能和基质能量输入），为 82% +/- 8%，而 G. sulfurreducens 为 77% +/- 2%，G. metallireducens 为 78% +/- 5%，这是由于混合菌的库仑效率更高。在 0.4 V 的外加电压下，混合培养物 MEC 中甲烷的产量增加，导致氢气回收率降低，总能量回收率从 G. sulfurreducens 的 80% +/- 5%和 G. metallireducens 的 76% +/- 0%下降到 38% +/- 16%。内部氢气回收得到了证实，因为当向混合菌中通入氢气时，其产生了稳定的电流密度为 31 +/- 0 A/m3，而 G. sulfurreducens 的电流产生则稳定下降。群落分析表明，尽管在从微生物燃料电池反应器获得的混合培养物接种物中相对缺乏（2%的克隆），但 G. sulfurreducens 在混合培养物 MEC 中占优势（72%的克隆）。这些结果表明，Geobacter 属的细菌在 MEC 中能够获得与混合培养物相似的产氢率和能量回收率，并且混合培养物 MEC 中的高库仑效率部分归因于氢气向电流的循环回收。
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