College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China.
Fujian Provincial Key Laboratory of Eco-Industrial Green Technology, College of Ecology and Resources Engineering, Wuyi University, Wuyishan, 354300, China.
World J Microbiol Biotechnol. 2024 Sep 16;40(10):321. doi: 10.1007/s11274-024-04125-5.
Laccases act as green catalysts for oxidative cross-coupling of phenolic antioxidnt compounds, but low stability and non-recyclability limit its application. To address that, metal-organic frameworks Cu-BTC and Cr-MOF were synthesized as supports to immobilize the efficient laccase from Cerrena sp. HYB07. The Brunauer-Emmett-Teller surface area of Cu-BTC and Cr-MOF were 1213.2 and 907.1 m/g, respectively. The two carriers respectively presented pore diameters of 1.2-10 nm and 1.4-12 nm as octahedron, indicating nano-scale mesoporosity. These Cu-BTC and Cr-MOF carriers could adsorb laccase with enzyme loading of 1933.2 and 1564.4 U/g carrier, respectively. The stability and organic solvent tolerance of Cu-BTC-laccase and Cr-MOF-laccase were both obviously improved compared to free laccase. Thermal inactivation kinetics showed that both the two immobilized laccases displayed lower thermal inactivation rate constants. Importantly, the Cu-BTC-laccase and Cr-MOF-laccase both showed much higher activity for cross-coupling of ethyl ferulate than free laccase, which had 2.5-fold higher cross-coupling efficiency than that by free laccase. The ethyl ferulate coupling product was also analyzed by mass spectroscopy and the synthesis pathway of ethyl ferulate dimer was proposed. The cross coupling of ethyl ferulate required the formation of radical intermediates of ethyl ferulate generated by laccase mediated oxidation. This work paved the way for MOFs immobilized laccase for cross coupling of antioxidant phenols.
漆酶可作为酚类抗氧化剂化合物氧化交叉偶联的绿色催化剂，但稳定性低和不可回收性限制了其应用。为了解决这个问题，合成了金属有机骨架 Cu-BTC 和 Cr-MOF 作为固定化高效漆酶（Cerrena sp. HYB07）的载体。Cu-BTC 和 Cr-MOF 的 Brunauer-Emmett-Teller 比表面积分别为 1213.2 和 907.1 m/g，孔径分别为 1.2-10nm 和 1.4-12nm，呈八面体，表明具有纳米级介孔。这两种载体分别可以吸附 1933.2 和 1564.4 U/g 载体的漆酶，其酶负载量分别为 1933.2 和 1564.4 U/g 载体。与游离漆酶相比，Cu-BTC-漆酶和 Cr-MOF-漆酶的稳定性和有机溶剂耐受性均明显提高。热失活动力学表明，两种固定化漆酶的热失活速率常数均较低。重要的是，Cu-BTC-漆酶和 Cr-MOF-漆酶在催化乙基阿魏酸交叉偶联方面的活性均明显高于游离漆酶，其交叉偶联效率比游离漆酶高 2.5 倍。还通过质谱分析了乙基阿魏酸偶联产物，并提出了乙基阿魏酸二聚体的合成途径。乙基阿魏酸的交叉偶联需要通过漆酶介导的氧化生成的乙基阿魏酸自由基中间体的形成。这项工作为金属有机骨架固定化漆酶在抗氧化酚类化合物的交叉偶联方面铺平了道路。
