Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
Securing Antarctica's Environmental Future, Monash University, Clayton, VIC 3800, Australia.
Biochem Soc Trans. 2023 Oct 31;51(5):1921-1933. doi: 10.1042/BST20230120.
The splitting of hydrogen (H2) is an energy-yielding process, which is important for both biological systems and as a means of providing green energy. In biology, this reaction is mediated by enzymes called hydrogenases, which utilise complex nickel and iron cofactors to split H2 and transfer the resulting electrons to an electron-acceptor. These [NiFe]-hydrogenases have received considerable attention as catalysts in fuel cells, which utilise H2 to produce electrical current. [NiFe]-hydrogenases are a promising alternative to the platinum-based catalysts that currently predominate in fuel cells due to the abundance of nickel and iron, and the resistance of some family members to inhibition by gases, including carbon monoxide, which rapidly poison platinum-based catalysts. However, the majority of characterised [NiFe]-hydrogenases are inhibited by oxygen (O2), limiting their activity and stability. We recently reported the isolation and characterisation of the [NiFe]-hydrogenase Huc from Mycobacterium smegmatis, which is insensitive to inhibition by O2 and has an extremely high affinity, making it capable of oxidising H2 in air to below atmospheric concentrations. These properties make Huc a promising candidate for the development of enzyme-based fuel cells (EBFCs), which utilise H2 at low concentrations and in impure gas mixtures. In this review, we aim to provide context for the use of Huc for this purpose by discussing the advantages of [NiFe]-hydrogenases as catalysts and their deployment in fuel cells. We also address the challenges associated with using [NiFe]-hydrogenases for this purpose, and how these might be overcome to develop EBFCs that can be deployed at scale.
氢气（H2）的分裂是一个产能过程，它对生物系统和提供绿色能源都很重要。在生物学中，这种反应是由称为氢化酶的酶介导的，氢化酶利用复杂的镍和铁辅因子来分裂 H2，并将产生的电子转移到电子受体。这些 [NiFe]-氢化酶作为燃料电池中的催化剂受到了相当多的关注，燃料电池利用 H2 产生电流。[NiFe]-氢化酶是目前在燃料电池中占主导地位的铂基催化剂的有前途的替代品，因为镍和铁丰富，并且一些家族成员对包括一氧化碳在内的气体的抑制具有抗性，一氧化碳会迅速使铂基催化剂中毒。然而，大多数已鉴定的 [NiFe]-氢化酶会被氧气（O2）抑制，限制了它们的活性和稳定性。我们最近报道了从耻垢分枝杆菌中分离和表征的 [NiFe]-氢化酶 Huc，它对 O2 的抑制不敏感，并且具有极高的亲和力，使其能够在空气中将 H2 氧化到低于大气浓度。这些特性使 Huc 成为基于酶的燃料电池（EBFC）的有前途的候选物，EBFC 可以在低浓度和不纯的气体混合物中利用 H2。在这篇综述中，我们旨在通过讨论 [NiFe]-氢化酶作为催化剂的优势及其在燃料电池中的部署，为将 Huc 用于此目的提供背景。我们还讨论了为此目的使用 [NiFe]-氢化酶所涉及的挑战，以及如何克服这些挑战来开发可以大规模部署的 EBFC。
