Glycerol is an organic waste material that can be used for the production of microbial biomass, consequently providing valuable biocatalysts promoting the generation of electrical current in microbial fuel cells (MFCs). [NiFe]-Hydrogenases (Hyds) of Escherichia coli and Ralstonia eutropha may be applied as potential anode biocatalysts in MFCs. In this study, E. coli K12 whole cells or crude extracts and R. eutropha HF649 synthesizing Strep-tagged membrane-bound Hyds (MBH) were evaluated as anode enzymes in a bioelectrochemical system. The samples were immobilized on the sensors with polyvinyl acetate support. Mediators like ferrocene and its derivatives (ferrocene-carboxy-aldehyde, ferrocene-carboxylic acid, methyl-ferrocene-methanol) were employed. The maximal level of bioelectrocatalytic activity of Hyds was demonstrated at 500 mV voltage. Depending on the mediator and biocatalyst, current strength varied from 5 to 42 μA. Introduction of ferrocene-carboxylic acid enhanced current strength; moreover, the current flow was directly correlated with H2 concentration. The maximal value (up to 150 μA) of current strength was achieved with a 2-fold hydrogen supply. It may be inferred that Hyds are efficiently produced by E. coli and R. eutropha grown on glycerol, while ferrocene derivatives act as agents mediating the electrochemical activity of Hyds.

中文翻译：

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应用有机废甘油生产细菌细胞粗提物和微生物氢化酶-生物电化学系统的阳极酶。

甘油是一种有机废料，可用于生产微生物生物质，因此提供了宝贵的生物催化剂，可促进微生物燃料电池（MFCs）中电流的产生。大肠杆菌和富营养小球菌的[NiFe]-加氢酶（Hyds）可用作MFC中的潜在阳极生物催化剂。在这项研究中，大肠杆菌K12全细胞或粗提物和富营养的R. eutropha HF649合成带有Strep标签的膜结合Hyds（MBH）被评估为生物电化学系统中的阳极酶。用聚乙酸乙烯酯支持物将样品固定在传感器上。使用诸如二茂铁及其衍生物（二茂铁-羧基-醛，二茂铁-羧酸，甲基二茂铁-甲醇）的介体。在500 mV电压下证明了Hyds的最大生物电催化活性。取决于介体和生物催化剂，电流强度在5至42μA之间变化。引入二茂铁羧酸增强了电流强度；此外，电流与H 2浓度直接相关。使用2倍的氢气供应可达到电流强度的最大值（高达150μA）。可以推断，Hyds是由在甘油上生长的大肠杆菌和富营养富营养菌有效产生的，而二茂铁衍生物则充当介导Hyds电化学活性的试剂。