Park Doo Hyun, Zeikus J Gregory
Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA.
Biotechnol Bioeng. 2003 Feb 5;81(3):348-55. doi: 10.1002/bit.10501.
A new one-compartment fuel cell was composed of a rubber bunged bottle with a center-inserted anode and a window-mounted cathode containing an internal, proton-permeable porcelain layer. This fuel cell design was less expensive and more practical than the conventional two-compartment system, which requires aeration and a ferricyanide solution in the cathode compartment. Three new electrodes containing bound electron mediators including a Mn(4+)-graphite anode, a neutral red (NR) covalently linked woven graphite anode, and an Fe(3+)-graphite cathode were developed that greatly enhanced electrical energy production (i.e., microbial electron transfer) over conventional graphite electrodes. The potentials of these electrodes measured by cyclic voltametry at pH 7.0 were (in volts): +0.493 (Fe(3+)-graphite); +0.15 (Mn(4+)-graphite); and -0.53 (NR-woven graphite). The maximal electrical productivities obtained with sewage sludge as the biocatalyst and using a Mn(4+)-graphite anode and a Fe(3+)-graphite cathode were 14 mA current, 0.45 V potential, 1,750 mA/m(2) current density, and 788 mW/m(2) of power density. With Escherichia coli as the biocatalyst and using a Mn(4+)-graphite anode and a Fe(3+)-graphite cathode, the maximal electrical productivities obtained were 2.6 mA current, 0.28 V potential, 325 mA/m(2) current density, and 91 mW/m(2) of power density. These results show that the amount of electrical energy produced by microbial fuel cells can be increased 1,000-fold by incorporating electron mediators into graphite electrodes. These results also imply that sewage sludge may contain unique electrophilic microbes that transfer electrons more readily than E. coli and that microbial fuel cells using the new Mn(4+)-graphite anode and Fe(3+)-graphite cathode may have commercial utility for producing low amounts of electrical power needed in remote locations.
一种新型单室燃料电池由一个带有中心插入式阳极的橡胶塞瓶和一个安装有窗口阴极的电池组成，阴极内部有一层质子可渗透的瓷层。这种燃料电池设计比传统的双室系统成本更低、更实用，传统双室系统需要在阴极室进行曝气并使用铁氰化物溶液。开发了三种含有结合电子介质的新型电极，包括Mn(4 +)-石墨阳极、中性红（NR）共价连接的编织石墨阳极和Fe(3 +)-石墨阴极，与传统石墨电极相比，这些电极大大提高了电能产生（即微生物电子转移）。在pH 7.0下通过循环伏安法测量的这些电极的电位（以伏特为单位）为：+0.493（Fe(3 +)-石墨）；+0.15（Mn(4 +)-石墨）；和 -0.53（NR-编织石墨）。以污水污泥作为生物催化剂，使用Mn(4 +)-石墨阳极和Fe(3 +)-石墨阴极获得的最大电生产率为14 mA电流、0.45 V电位、1750 mA/m²电流密度和788 mW/m²功率密度。以大肠杆菌作为生物催化剂，使用Mn(4 +)-石墨阳极和Fe(3 +)-石墨阴极，获得的最大电生产率为2.6 mA电流、0.28 V电位、325 mA/m²电流密度和91 mW/m²功率密度。这些结果表明，通过将电子介质纳入石墨电极，微生物燃料电池产生的电量可以增加1000倍。这些结果还意味着污水污泥可能含有比大肠杆菌更容易转移电子的独特亲电微生物，并且使用新型Mn(4 +)-石墨阳极和Fe(3 +)-石墨阴极的微生物燃料电池可能具有商业用途，可用于产生偏远地区所需的少量电力。
