Microbial fuel cells installed in rice paddy fields (RP-MFCs) are able to serve as on-site batteries for operating low-power environmental sensors. In order to increase the utility and reliability of RP-MFCs, however, further research is necessary for boosting the power output. Here we examined several powdered iron species, including zero valent iron (ZVI), goethite, and magnetite, for their application to increasing power outputs from RP-MFCs. Soil around anodes was supplemented with either of these iron species, and RP-MFCs were operated for several months during the transplanting and harvesting. It was found that power outputs from RP-MFCs supplemented with ZVI were more than double the outputs from control (not supplemented with iron species) and other RP-MFCs, even after iron corrosion was ceased, and the maximum power density reached 130 mW/m² (per projected area of the anode). Metabarcoding of 16S rRNA gene amplicons suggested that several taxa represented by fermentative and exoelectrogenic bacteria were substantially increased in MFCs supplemented with ZVI. Results suggest that ZVI lowers oxidation/reduction potential around anodes, activates anaerobic microbes involved in the conversion of organic matter into electricity and increases power output from RP-MFCs.

安装在稻田（RP-MFC）中的微生物燃料电池可作为现场电池，用于运行低功率环境传感器。但是，为了提高RP-MFC的实用性和可靠性，需要进一步研究以提高功率输出。在这里，我们研究了几种铁粉，包括零价铁（ZVI），针铁矿和磁铁矿，它们在增加RP-MFC的功率输出中的应用。在阳极周围的土壤中补充了这两种铁中的任何一种，在移植和收获期间，RP-MFCs运行了几个月。研究发现，即使停止了铁腐蚀，补充了ZVI的RP-MFC的功率输出也比对照品（不补充铁）和其他RP-MFC的功率高出一倍以上，²（阳极的每个投影面积）。对16S rRNA基因扩增子的元条形码表明，在补充ZVI的MFC中，以发酵和外生电细菌为代表的几种分类单元显着增加。结果表明，ZVI降低了阳极周围的氧化/还原电势，激活了将有机物转化为电能的厌氧微生物，并增加了RP-MFC的功率输出。