Novel strategy for three-dimensional real-time imaging of microbial fuel cell communities: monitoring the inhibitory effects of proton accumulation within the anode biofilm
Novel strategy for three-dimensional real-time imaging of microbial fuel cell communities: monitoring the inhibitory effects of proton accumulation within the anode biofilm
复制标题
DOI：
10.1039/b816445b
复制
发表时间：
2009-01-01
影响因子：
32.5
通讯作者：
Lovley, Derek R.
中科院分区：
文献类型：
--
作者：
Franks, Ashley E.;Nevin, Kelly P.;Lovley, Derek R.
利用微生物燃料电池（MFC）从环境、有机废物或可再生生物质中获取电力是一种颇具吸引力的策略，但研究阳极相关生物膜所需的破坏性采样阻碍了旨在更好地理解和优化微生物-阳极相互作用的研究。因此，开发了一种能够使用共焦扫描激光显微镜对阳极生物膜进行实时成像的 MFC。在这种新型 MFC 硫还原地杆菌中，一种与 MFC 阳极上常见的微生物密切相关的生物体，能够产生高电流密度，产生的电流与之前报道的其他 MFC 设计相当。 G.sulfurreducens 被设计用来产生荧光蛋白 mcherry，以促进实时成像，产生的电流与野生型细胞相当。将 pH 敏感荧光探针 C-SNARF-4 引入阳极室，显示阳极生物膜内存在强烈的 pH 梯度。 pH值随着与阳极表面的距离的增加以及从生物膜柱的外部到内部的增加而降低。阳极表面附近的 pH 水平低至 6.1。 7 在外部介质中。各种控制表明质子积累与电流产生有关。将培养基的 pH 从 7 降至 6 严重限制了硫还原杆菌的生长。这些结果表明，实时无损监测阳极生物膜的活性是可行的，并表明阳极生物膜内有机物氧化释放的质子的积累会限制电流的产生。
Harvesting electricity from the environment, organic wastes, or renewable biomass with microbial fuel cells (MFCs) is an appealing strategy, but the destructive sampling required to investigate the anode-associated biofilms has hampered research designed to better understand and optimize microbe-anode interactions. Therefore, a MFC that permits real-time imaging of the anode biofilm with confocal scanning laser microscopy was developed. In this new MFC Geobacter sulfurreducens, an organism closely related to those often found on MFC anodes and capable of high current densities, produced current comparable to that previously reported with other MFC designs. G. sulfurreducens engineered to produce the fluorescent protein mcherry to facilitate real-time imaging produced current comparable to wild-type cells. Introducing C-SNARF-4, a pH-sensitive fluoroprobe, into the anode chamber revealed strong pH gradients within the anode biofilms. The pH decreased with increased proximity to the anode surface and from the exterior to the interior of biofilm pillars. Near the anode surface pH levels were as low as 6.1 compared to ca. 7 in the external medium. Various controls demonstrated that the proton accumulation was associated with current production. Dropping the pH of culture medium from 7 to 6 severely limited the growth of G. sulfurreducens. These results demonstrate that it is feasible to non-destructively monitor the activity of anode biofilms in real time and suggest that the accumulation of protons that are released from organic matter oxidation within anode biofilms can limit current production.