Ruth John C, Milton Ross D, Gu Wenyu, Spormann Alfred M
Department of Chemical Engineering, E250 James. H. Clark Center, Stanford University, 318 Campus Drive, Stanford, CA, 94305, USA.
Department of Civil and Environmental Engineering, E250 James. H. Clark Center, Stanford University, 318 Campus Drive, Stanford, CA, 94305, USA.
Chemistry. 2020 Jun 5;26(32):7323-7329. doi: 10.1002/chem.202000750. Epub 2020 May 11.
Molecular hydrogen is a major high-energy carrier for future energy technologies, if produced from renewable electrical energy. Hydrogenase enzymes offer a pathway for bioelectrochemically producing hydrogen that is advantageous over traditional platforms for hydrogen production because of low overpotentials and ambient operating temperature and pressure. However, electron delivery from the electrode surface to the enzyme's active site is often rate-limiting. Here, it is shown that three different hydrogenases from Clostridium pasteurianum and Methanococcus maripaludis, when immobilized at a cathode in a cobaltocene-functionalized polyallylamine (Cc-PAA) redox polymer, mediate rapid and efficient hydrogen evolution. Furthermore, it is shown that Cc-PAA-mediated hydrogenases can operate at high faradaic efficiency (80-100 %) and low apparent overpotential (-0.578 to -0.593 V vs. SHE). Specific activities of these hydrogenases in the electrosynthetic Cc-PAA assay were comparable to their respective activities in traditional methyl viologen assays, indicating that Cc-PAA mediates electron transfer at high rates, to most of the embedded enzymes.
如果由可再生电能产生，分子氢将成为未来能源技术的主要高能载体。氢化酶为生物电化学产氢提供了一条途径，与传统制氢平台相比具有优势，因为其过电位低，操作温度和压力为环境条件。然而，从电极表面到酶活性位点的电子传递通常是限速步骤。本文表明，来自巴氏梭菌和沼泽甲烷球菌的三种不同氢化酶，当固定在钴茂官能化聚烯丙胺（Cc-PAA）氧化还原聚合物修饰的阴极上时，能介导快速高效的析氢反应。此外，研究表明，Cc-PAA介导的氢化酶能在高法拉第效率（80-100%）和低表观过电位（相对于标准氢电极，为-0.578至-0.593 V）下运行。这些氢化酶在电合成Cc-PAA测定中的比活性与其在传统甲基紫精测定中的各自活性相当，表明Cc-PAA能以高速率介导电子转移至大多数嵌入的酶。
