Goldhahn Christian, Taut Josef A, Schubert Mark, Burgert Ingo, Chanana Munish
ETH Zürich, Institute for Building Materials Stefano-Franscini-Platz 3 8093 Zürich Switzerland
Empa - Swiss Federal Laboratories for Material Science and Technology, Cellulose & Wood Materials Überlandstrasse 129 8600 Dübendorf Switzerland.
RSC Adv. 2020 Jun 1;10(35):20608-20619. doi: 10.1039/c9ra10633b. eCollection 2020 May 27.
Enzymes are often immobilized on solid supports to enable their recovery from reaction solutions, facilitate their reuse and hence increase cost-effectiveness in their application. Immobilized enzymes may even be used for flow-through applications in continuous processes. However, the synthesis of traditional immobilization scaffolds and immobilization techniques lack sustainability as they are often based on fuel-based materials and tedious synthesis- and immobilization approaches. Here, we present the natural material wood as a green alternative for enzyme immobilization. Its natural structure provides a mechanically stable porous scaffold with a high inner surface area that allows for directional flow-through of liquids. Enzymes were immobilized by nanoparticle-mediated adsorption, a simple, versatile and completely water-based process. The resulting wood-enzyme hybrids were intensely investigated for the model enzyme laccase. Reaction kinetics, as well as catalytic activities at various pH-values, temperatures, and ionic strengths were determined. The wood-enzyme hybrids could quickly and completely be removed from the reaction solution. Hence, they allow for multifold reusability. We show a series of 25 consecutive reaction cycles with a remaining activity in the last cycle of 90% of the maximal activity. Moreover, the anisotropic porosity of wood enabled the application of the hybrid material as a biocatalytic flow-through reactor. Flow-rate dependent productivity of a single-enzyme reaction was determined. Moreover, we show a two-step reaction cascade in continuous flow by the immobilization of the enzymes glucose oxidase and horseradish peroxidase. Therefore, the natural material wood proved to be a promising material for application in continuous-flow biocatalysis.
酶通常固定在固体载体上，以便从反应溶液中回收，便于重复使用，从而提高其应用的成本效益。固定化酶甚至可用于连续过程中的流通应用。然而，传统固定化支架的合成和固定化技术缺乏可持续性，因为它们通常基于燃料基材料以及繁琐的合成和固定方法。在此，我们提出天然材料木材作为酶固定化的绿色替代品。其天然结构提供了一种机械稳定的多孔支架，具有高内表面积，允许液体定向流通。酶通过纳米颗粒介导的吸附进行固定，这是一种简单、通用且完全基于水的过程。对所得的木材 - 酶杂化物针对模型酶漆酶进行了深入研究。测定了反应动力学以及在各种pH值、温度和离子强度下的催化活性。木材 - 酶杂化物能够快速且完全地从反应溶液中去除。因此，它们具有多次重复使用性。我们展示了一系列连续25个反应循环，最后一个循环中的剩余活性为最大活性的90%。此外，木材的各向异性孔隙率使得该杂化材料能够用作生物催化流通反应器。测定了单酶反应的流速依赖性生产率。此外，我们通过固定化葡萄糖氧化酶和辣根过氧化物酶展示了连续流中的两步反应级联。因此，天然材料木材被证明是一种有前途的材料，可应用于连续流生物催化。
