Construction of a combined enzyme system of graphene oxide and manganese peroxidase for efficient oxidation of aromatic compounds.
Construction of a combined enzyme system of graphene oxide and manganese peroxidase for efficient oxidation of aromatic compounds.
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DOI：
10.1039/d0nr00408a
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发表时间：
2020-03
期刊：
影响因子：
6.7
通讯作者：
Shichao Yang;Jun Yang;Tao Wang;Liuqing Li;S. Yu;R. Jia;Ping Chen
中科院分区：
文献类型：
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作者：
Shichao Yang;Jun Yang;Tao Wang;Liuqing Li;S. Yu;R. Jia;Ping Chen
白齿耙齿菌（Irpex lacteus）F17的锰过氧化物酶（MnP）具有独特的性质和降解有害芳香化合物的能力，在环境生物技术领域具有潜在的生物催化作用。但其反应条件苛刻，催化活性不足，限制了其实际应用。在这里，我们结合联合收割机氧化石墨烯（GO）和锰过氧化物酶构建一个高效的酶系统（GO-MNP），具有提高的催化效率和广泛的pH范围的芳香族物质的氧化和染料脱色。结果表明，GO-MnP对Mn ~（2+）的米氏常数（Km）比MnP低2.8倍，催化效率（kcat/Km）比MnP高4.5倍;在pH 4.5 ~ 5.5范围内，GO-MnP对多种染料的脱色效果显著。中点氧化还原电位的比较也反映了GO-MnP的强氧化能力。此外，我们证明，在GO-MNP系统中，MNP活性主要取决于GO中的环氧基和羧基的量，基于GO和还原GO中的官能团的变化与不同的还原度的分析，如通过X射线光电子能谱所示。
Manganese peroxidase (MnP) from Irpex lacteus F17 has potential use as a biocatalyst in the field of environmental biotechnology because of its unique properties and ability to decompose harmful aromatic compounds. However, its requirement of harsh acidic reaction conditions and its insufficient catalytic activity restrict its practical applications. Here, we combine graphene oxide (GO) and MnP to construct an efficient enzyme system (GO-MnP) with improved catalytic efficiencies and a wide pH range for the oxidation of aromatic substances and dye decolorization. We found that the Michaelis constant (Km) of GO-MnP for Mn2+ was 2.8 times lower and the catalytic efficiency (kcat/Km) of GO-MnP was 4.5 times higher than those of MnP, and that the decolorization of various dyes by GO-MnP was significantly improved over the pH range of 4.5-5.5. A comparison of the midpoint redox potentials also reflects the strong oxidation ability of GO-MnP. Furthermore, we demonstrated that, in the GO-MnP system, the MnP activity is mainly determined by the amounts of epoxy and carboxyl groups in GO, based on an analysis of the functional group changes in GO and reduced GO associated with different reduction degrees as shown by X-ray photoelectron spectroscopy.