Kaku Nobuo, Yonezawa Natsuki, Kodama Yumiko, Watanabe Kazuya
Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata, Japan.
Appl Microbiol Biotechnol. 2008 May;79(1):43-9. doi: 10.1007/s00253-008-1410-9. Epub 2008 Mar 5.
Soils are rich in organics, particularly those that support growth of plants. These organics are possible sources of sustainable energy, and a microbial fuel cell (MFC) system can potentially be used for this purpose. Here, we report the application of an MFC system to electricity generation in a rice paddy field. In our system, graphite felt electrodes were used; an anode was set in the rice rhizosphere, and a cathode was in the flooded water above the rhizosphere. It was observed that electricity generation (as high as 6 mW/m(2), normalized to the anode projection area) was sunlight dependent and exhibited circadian oscillation. Artificial shading of rice plants in the daytime inhibited the electricity generation. In the rhizosphere, rice roots penetrated the anode graphite felt where specific bacterial populations occurred. Supplementation to the anode region with acetate (one of the major root-exhausted organic compounds) enhanced the electricity generation in the dark. These results suggest that the paddy-field electricity-generation system was an ecological solar cell in which the plant photosynthesis was coupled to the microbial conversion of organics to electricity.
土壤富含有机物，尤其是那些支持植物生长的土壤。这些有机物是可持续能源的潜在来源，微生物燃料电池（MFC）系统有可能用于此目的。在此，我们报告了MFC系统在稻田发电中的应用。在我们的系统中，使用了石墨毡电极；阳极设置在水稻根际，阴极设置在根际上方的淹水区域。观察到发电（高达6 mW/m²，以阳极投影面积归一化）依赖于阳光并呈现昼夜振荡。白天对水稻植株进行人工遮荫会抑制发电。在根际，水稻根系穿透阳极石墨毡，特定细菌种群在那里出现。向阳极区域补充乙酸盐（主要的根系分泌有机化合物之一）可增强黑暗中的发电。这些结果表明，稻田发电系统是一种生态太阳能电池，其中植物光合作用与有机物向电能的微生物转化相耦合。
