| 摘要: | 酵素具有促進生化反應、專一性反應及可調節性等性質，常見於食品、工業以及飼料的應用。然而酵素大多需要在溫和的環境下作用，所以對於較為嚴苛的產業應用條件，酵素需透過固定化以提高其穩定性，並提供回收再利用的可能性來降低成本。因此本實驗室在2015年首次開發類沸石咪唑骨架材料-90 (ZIF-90)包封過氧化氫酶(Catalase)的原位創新合成法(de novo approach)，使酵素能在水相室溫的溫和環境下固定在生成的類沸石咪唑骨架材料中，在避免酵素展開而失活的同時，透過材料的孔洞使受質進入反應並防止蛋白質水解酶的作用，提供染整工業廢水的處理方法。後續，本實驗室在2019年以液體輔助機械力球磨法(Liquid‐Assisted Grinding Mechanochemistry)成功將酵素包封在ZIF-8、UiO-66-NH2和 Zn-MOF-74等有機金屬骨架材料中，在使用少量有機溶劑的前提下，保持酵素良好的生物活性，並提高合成的效率以及產量，提供有機金屬骨架包封酵素材料合成的另一種思維。因此，透過使用微量的溶劑在短時間合成大量生物性複合材料的液體輔助機械力球磨法，能有效的提升工業應用上的效益，賦予有機金屬骨架包封酵素材料更強的競爭力。
本篇論文成功的在液體輔助機械力球磨法的條件下，以更短的時間合成具有更高產率和良好酵素活性的ZIF-90包封過氧化氫酶材料。為了更進一步了解，酵素包覆以及晶體形成的關係，利用包封不同的酵素和改變合成環境的測試，提出可透過改變溶液pH值來調控酵素/奈米氧化鋅表面電位進而促使有機金屬骨架材料快速形成的理論，並提供一個可判斷Protein–Metal–organic Frameworks是否能生成的簡易方法。
;With the properties of highly specific for their reactant and products as well as promoting biochemical reactions, enzymes are commonly used in food, industry, and feed applications. However, most enzymes need to work in a mild and water-based environment with displaying optimum catalytic rate. In order to improve their stability in harsh conditions and provide the possibility of recycling to reduce costs, enzyme immobilization is a good way to achieve. In 2015, our laboratory first developed a de novo approach to embed enzymes in zeolitic imidazolate framework-90 (ZIF-90), a sub group of Metal-organic Frameworks (MOFs). In this work, we successful demonstrated that the enzyme is able to be encapsulated inside of MOFs under the mild aqueous phase and at room temperature and meanwhile the obtained biocomposites can avoid damages from protenase, the proteolytic enzyme, due to shielding by ZIF apertures. Subsequently, we also successfully demonstrated enzymes encapsulating in MOFs such as ZIF-8, UiO-66-NH2, and Zn-MOF-74 by liquid-assisted grinding mechanochemistry. The MOF enzyme biocomposites can maintain the biological activity of enzymes and the protein encapsulation efficiency and product yield of synthesis are improved. This work represents a step toward the creation of a suite of biomolecule in-MOF composites for application in a variety of industrial processes.
In this work, we use liquid-assisted grinding mechanochemistry to synthesize CAT@ZIF-90 with high yield and showing good bioactivity. To further understand the relationship between enzyme encapsulation and crystal formation, a various of enzymes are used and the synthetic conditions are adjusted. Finally, the judgment of the Protein–Metal-organic Frameworks formation is clarified. Only if the zeta potential of the enzyme/metal ion is negative, the MOFs will be formed. Besides, adjusting the surface potential of the enzyme/metal ion by changing the pH value of the solution is proposed. Different from the known method, it can avoid enzymes from losing their activity by structural change. Through zetasizer to easily distinguish the possibility of enzyme assistance in MOFs construction, and adjust the condition by the buffer to reach the requirement. This brand new thought will not only provide a great chance to build MOFs which are hard to generate in aqueous solution but also encapsulate enzymes to have extra application. |
