Fundamental Research on the Development of Bioelectrochemical Cells

1悬浮在缓冲溶液中的普通脱硫弧菌（Desulfovibrio vulgaris）全细胞作为均相催化剂，在甲基紫素（methyl viologen， MV）存在下产生电化学催化电流，用于H_<>的产生和消耗。用生物电催化理论对催化电流进行了分析，结果表明，丹顶草细胞中的氢化酶作为一种非常有效的催化剂，促进了H^+/H_2对的间接电化学氧化还原反应。因此，在温和的环境温度下，如中性ph下，该反应是可逆的。计算出该反应的速率是扩散控制的，这表明利用细菌细胞构建生物电化学电池的功能阳极是很有希望的同样，当Fe(CN)_6^<3->/Fe(CN)_6^<4->氧化还原偶对作为细菌之间的电子传递介质时，氧化亚铁硫杆菌作为催化剂将O_<>电化学还原为H_<>O。氧化亚铁细胞的转化也非常有效，对溶液中O_2的消耗产生了很大的催化阴极电流。因此，当我们希望在中性ph下操作生物电化学电池时，T.ferrooxidans不能作为O_2电化学还原的最佳生物催化剂。a .aceti以2-甲基-5,6-二甲氧基苯醌（Q_0）作为电子载体催化乙醇的氧化。对细菌的电催化行为进行了详细的研究，利用极谱动力学电流理论对催化电流进行了分析，由此计算出细菌细胞与Q_0之间的双分子速率常数非常大。该系统适用于以乙醇为燃料的生物电化学电池的构建对碳毡作为一种大电流输出电极进行了简要的研究，发现它是一种很有前途的生物电化学电池电极材料。少

1 Whole cells of Desulfovibrio vulgaris suspended in a buffer solution function as homogeneous catalysts to produce an electrochemical catalytic current for the production and consumption of H_<> in the presence of methyl viologen (MV). Analysis of the catalytic current by the theory of bioelectrocatalysis revealed that hydrogenase in the D.vulgaris cells function as a very effective catalyst to promote the indirect electrochemical redox reaction of H^+/H_2 couple. Thus, the reaction proceeds reversibly under such mild conditions as an ambient temperature at neutral pH.The rate of the reaction is calculated to be diffusion- controlled, indicating that the use of the bacterial cells is very promising for constructing a functional anode of bioelectrochemical cells.2 Similarly, Thiobacillus ferrooxidans functioned as a catalyst for the electorchemical reduction of O_<> to H_<>O when Fe(CN)_6^<3->/Fe(CN)_6^<4-> redox couple was employed as an electron transfer mediator between the bacteria … More l cells and an electrode. The conversion by T.ferrooxidans cells was also very effective to produce a large catalytic cathodic current for the consumption of O_2 in solution. However, the high catalytic activity was observed only at acidic pH.Consequently, T.ferrooxidans is concluded not to be a best choice as a biocatalyst for the electrochemical reduction of O_2 when we would like to operate bioelectrochemical cells at neutral pH.3 A.aceti catalyzes the oxidation of ethanol with 2-methyl-5,6-dimethoxy benzoquinone (Q_0) as an electron carrier. The electrocatalytic behavior was studied in detail, the theory of polarographic kinetic current was available for analyzing the catalytic current, from which the bimolecular rate constant between the bacterial cell and Q_0 could be calculated to be very large. This system is applicable to the construction of bioelectrochemical cells which use ethanol as a fuel.4 Carbon felt was briefly examined as an electrode of large scale current out put, and found to be very promising as an electrode material of bioelectrochemical cells. Less