Although graphene oxide (GO) has great potential in the field of immobilized enzyme catalysts, the detailed effects of GO with different morphological structures on immobilized enzyme are not well understood. GOs were prepared from 8000 mesh and nanoscale graphite at different reaction temperatures, and used as carriers to immobilize alpha-amylase by cross-linking method. The properties of GOs were characterized through Atomic force microscope, Fourier-transformed infrared, X-ray photoelectron spectroscopy, Raman and UV-Vis. Furthermore, the dosage of cross-linking agent, cross-linking time, optimum temperature/pH, thermal/pH/storage stability, reusability and kinetic parameters of immobilized enzymes were investigated. The results showed that the loading of alpha-amylase on GOs was 162.3-274.2 mg g-1. The reusability experiments revealed high activity maintenance of immobilized alpha-amylase even after seven reaction cycles. Moreover, the storage stability of immobilized enzyme improved via immobilization in comparison with free one and it maintained over 70% of their initial activity after 20 days storage at 4 °C.

中文翻译：

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共价法研究不同形态特征的氧化石墨烯对固定化酶性能的影响。

尽管氧化石墨烯（GO）在固定化酶催化剂领域具有巨大潜力，但对具有不同形态结构的GO对固定化酶的详细作用还没有很好的了解。GO是由8000目和纳米级石墨在不同的反应温度下制备的，并用作载体通过交联固定化α-淀粉酶。通过原子力显微镜，傅立叶变换红外光谱，X射线光电子能谱，拉曼光谱和紫外可见光谱对GO的性质进行了表征。此外，还研究了交联剂的用量，交联时间，最适温度/ pH，热/ pH /储存稳定性，固定化酶的可重复使用性和动力学参数。结果表明，GOs上α-淀粉酶的负载量为162.3-274.2 mg g-1。可重用性实验表明，即使经过七个反应周期，固定化的α-淀粉酶仍能保持较高的活性。而且，与游离的酶相比，固定化的酶的储存稳定性通过固定得到了改善，并且在4°C下储存20天后，其保持了其初始活性的70％以上。