Enzymes are biological catalysts intensively researched in several fields, including wastewater treatment. However, the structural vulnerability of enzymes limits their application. The design of enzyme mimetics is an interesting challenge in terms of selecting appropriate support for a (bio)mimetic and maintaining activity and stability after immobilization. In this work, a novel spherical solid composed of chitosan and magnetite nanoparticles was formulated to support hematin (as an oxidoreductase biomimetic). Magnetic chitosan beads were prepared via coprecipitation and gelation of Fe3O4 nanoparticles and chitosan, respectively. The solid combines chitosan advantages (non-toxicity, abundance, physicochemical stability, and flexibility to be shaped into beads) with nanoparticulated Fe3O4 properties (superparamagnetism and oxidoreductase mimic activity). A black solid with a regularly spherical shape, approximately 2 mm in diameter, was obtained. The solid was able to support hematin. Under optimal conditions, the incorporation of 3-aminopropyltriethoxysilane increased hematin immobilization efficiency. The synthesized solid presents catalase activity, decomposing 56 % of hydrogen peroxide under optimal conditions, while without hematin, it only decomposes 33 %. The solid presented catalytic activity and low leaching of iron in reaction medium, which makes it a potential catalyst to be applied in wastewater remediation in future work.

中文翻译：

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基于磁性壳聚糖珠的氧化还原酶仿生固定化新型催化剂的合成与表征


酶是在多个领域进行深入研究的生物催化剂，包括废水处理。然而，酶的结构脆弱性限制了它们的应用。酶模拟物的设计在为（生物）模拟物选择合适的支持物以及在固定后保持活性和稳定性方面是一个有趣的挑战。在这项工作中，配制了一种由壳聚糖和磁铁矿纳米颗粒组成的新型球形固体来支持血红素（作为一种氧化还原酶仿生物）。分别通过 Fe ₃ O ₄ 纳米颗粒和壳聚糖的共沉淀和凝胶化制备磁性壳聚糖珠。该固体结合了壳聚糖的优点（无毒、丰度、物理化学稳定性和可塑造成珠子的柔韧性）和纳米颗粒 Fe ₃ O ₄ 特性（超顺磁性和氧化还原酶模拟活性）。获得了一种具有规则球形的黑色固体，直径约为 2 毫米。固体能够支持血红素。在最佳条件下，3-氨丙基三乙氧基硅烷的掺入提高了血红素固定效率。合成的固体具有过氧化氢酶活性，在最佳条件下分解 56% 的过氧化氢，而没有血红素，它仅分解 33%。该固体具有催化活性，铁在反应介质中的浸出率低，使其成为未来工作中应用于废水修复的潜在催化剂。