Department of Biochemistry, Microbiology and Biotechnology, Yerevan State University, 1 A. Manoukian Str., 0025 Yerevan, Armenia.
Institute of Microbiology, NAS Belarus, 2 Kuprevich Str., 220141 Minsk, Belarus.
FEMS Microbiol Lett. 2020 Apr 1;367(7). doi: 10.1093/femsle/fnaa056.
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.
甘油是一种有机废物，可以用于生产微生物生物质，从而提供有价值的生物催化剂，促进微生物燃料电池 (MFC) 中电流的产生。大肠杆菌和罗尔斯顿氏菌中的 [NiFe]-氢化酶 (Hyd) 可以作为潜在的 MFC 阳极生物催化剂应用。在这项研究中，大肠杆菌 K12 全细胞或粗提取物和合成带有 Strep 标签的膜结合氢化酶 (MBH) 的 R. eutropha HF649 被评估为生物电化学系统中的阳极酶。这些样品用聚醋酸乙烯酯载体固定在传感器上。使用了介体，如二茂铁及其衍生物（二茂铁-羧醛、二茂铁羧酸、甲基二茂铁-甲醇）。Hyd 的最大生物电催化活性在 500 mV 电压下表现出来。根据介体和生物催化剂的不同，电流强度从 5 到 42 μA 不等。引入二茂铁羧酸增强了电流强度；此外，电流流动与 H2 浓度直接相关。在两倍氢气供应的情况下，电流强度达到了最大值（高达 150 μA）。可以推断，大肠杆菌和在甘油上生长的 R. eutropha 高效地生产了 Hyd，而二茂铁衍生物作为介导 Hyd 的电化学活性的试剂发挥作用。
