| 摘要: | 二氧化碳對地球暖化以及氣候變遷有重大的影響，而如何處理過量的二氧化碳則成了迫在眉睫的問題。近年利用蛋白質酵素(如甲酸脫氫酶等)進行二氧化碳的固定化，將無機的二氧化碳轉化成有機生物物質，為一項重要研究課題。然而酵素具有不穩定性，回收再利用性不高，因而限制了酵素的應用性。將酵素固定在固體載體上是一項常見提高穩定性的做法，而金屬有機骨架材料(MOFs)作為新興的多孔材料，能夠形成穩定的微型環境來保護酵素，具有空間侷限性能有效避免酵素失活，另外因為其高孔隙率、多樣的合成條件和可控制的結構等優勢，非常具有作為酵素固定化載體的潛力。
而本實驗室在2015年首次開發的原位創新合成法，成功在室溫且水相的環境中，將過氧化氫酶(CAT)封裝於類沸石咪唑骨架材料(ZIF-90)中，便是金屬有機骨架材料應用於酵素固定化的例子，利用金屬有機骨架材料的孔洞性，允許受質進入材料催化的同時又可以防止大分子蛋白質水解酶的作用。除酵素固定化之外，金屬有機骨架材料因其具有高表面積、可調孔徑和低熱容量的特性，使其成為應用於碳捕獲與儲存(CCS)的焦點。在已知的金屬有機骨架材料中，MOF-74類型的金屬有機骨架材料更因為其開放的金屬位點而表現出高度的二氧化碳吸附性能。
本篇論文研究，再次利用原位創新合成法，成功在生物友善且水相環境的環境下將甲酸脫氫酶(FDH)包覆於Zn-MOF-74中。同時，甲酸脫氫酶包封在Zn-MOF-74中，提升了酵素對酸鹼耐受性，使其於非活性範圍之pH值，例如飽和二氧化碳水溶液的pH = 6.1之下仍保有活性，且因為六邊形通道及開放的金屬位點，使被包封的酵素活性相較於未包封的酵素來的更佳，活性的差異可以來到200 %至300 %之多。
;Carbon dioxide (CO2) has led to global warming and climate change, making sustainable development crucial in chemistry. Enzymes such as formate dehydrogenase (FDH) are essential for efficient CO2 fixation, converting it into organic biomaterials. indeed, enzyme instability and reusability limitations present challenges that impede practical applications. However, ongoing research seeks to surmount these obstacles and unleash the potential of enzymes for a more sustainable future. One effective approach to enhance enzyme stability is immobilizing enzymes on solid carriers. Metal-organic frameworks (MOFs), known for their emerging porous materials, create stable microenvironments that shield enzymes and prevent denaturation. Additionally, MOFs offer advantages such as high porosity, diverse synthesis conditions, and tunable structures, making them exceptionally promising carriers for enzyme immobilization.
In our laboratory, we have pioneered an innovative one-pot method to encapsulate catalase (CAT) enzyme within Zeolite Imidazolate Framework-90 (ZIF-90) in mild water conditions. This remarkable example of enzyme immobilization with MOFs has significantly improved enzyme stability and reusability. Moreover, MOFs, such as MOF-74, exhibit outstanding CO2 adsorption even in humid conditions, showing great potential for carbon capture and storage applications.
This research study utilized a rapid de novo synthesis method to encapsulate FDH within Zn-MOF-74 under mild aqueous conditions. Notably, this encapsulation process improves the enzyme′s acid-base tolerance, enabling it to remain active even at pH levels outside its non-active range, such as the pH = 6.1 of saturated carbon dioxide aqueous solution. The hexagonal channels and open metal sites of Zn-MOF-74 significantly enhance enzyme activity compared to the unencapsulated form, resulting in a remarkable three-fold increase in activity. |
