Jana Partha Sarathi, Katuri Krishna, Kavanagh Paul, Kumar Amit, Leech Dónal
School of Chemistry & Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland.
Phys Chem Chem Phys. 2014 May 21;16(19):9039-46. doi: 10.1039/c4cp01023j.
Harnessing, and understanding the mechanisms of growth and activity of, biofilms of electroactive bacteria (EAB) on solid electrodes is of increasing interest, for application to microbial fuel and electrolysis cells. Microbial electrochemical cell technology can be used to generate electricity, or higher value chemicals, from organic waste. The capability of biofilms of electroactive bacteria to transfer electrons to solid anodes is a key feature of this emerging technology, yet the electron transfer mechanism is not fully characterized as yet. Acetate oxidation current generated from biofilms of an EAB, Geobacter sulfurreducens, on graphite electrodes as a function of time does not correlate with film thickness. Values of film thickness, and the number and local concentration of electrically connected redox sites within Geobacter sulfurreducens biofilms as well as a charge transport diffusion co-efficient for the biofilm can be estimated from non-turnover voltammetry. The thicker biofilms, of 50 ± 9 μm, display higher charge transport diffusion co-efficient than that in thinner films, as increased film porosity of these films improves ion transport, required to maintain electro-neutrality upon electrolysis.
利用并理解电活性细菌（EAB）在固体电极上生物膜的生长和活性机制，对于将其应用于微生物燃料电池和电解池而言，正变得越来越重要。微生物电化学电池技术可用于从有机废物中发电或生产更高价值的化学品。电活性细菌生物膜将电子转移到固体阳极的能力是这项新兴技术的一个关键特性，但电子转移机制尚未完全明确。在石墨电极上，嗜硫地杆菌这一电活性细菌的生物膜产生的醋酸盐氧化电流随时间的变化与膜厚度无关。膜厚度的值、嗜硫地杆菌生物膜内电连接的氧化还原位点的数量和局部浓度以及生物膜的电荷传输扩散系数可通过非周转伏安法估算。厚度为50±9μm的较厚生物膜显示出比薄生物膜更高的电荷传输扩散系数，因为这些膜增加的孔隙率改善了离子传输，而离子传输是电解时维持电中性所必需的。
