新型方法制备固定化脲酶基质材料及固定化脲酶的性能研究

摘要

以微晶纤维素(Microcrystalline cellulose，MCC)为原料，采用新型水热氧化方法，制备纤维素基质固定化脲酶载体材料-双醛纤维素(Dialdehyde cellulose, DAC)。采用红外光谱(IR)、固体核磁共振(CP/MAS 13C NMR)、X-射线衍射(XRD)和扫描电镜(SEM)表征产物结构。测试制备的纤维素基质固载脲酶的酶学性能，并与交联壳聚糖、双醛淀粉固载脲酶的酶学性能进行比较分析，构建酶学性能理论方程。结果表明：采用新型水热氧化反应可成功制备高醛基含量的氧化纤维素，与交联壳聚糖和双醛淀粉固定化脲酶相比，所得氧化纤维素载体材料固定化脲酶的米氏常数小(0.0108 mol⋅L-1)，对底物亲和能力强，重复使用率高，在 pH=5.0~9.0能保持酶活性，建立的理论方程较好地表征了固载酶酶学性能。%Dialdehyde cellulose (DAC), a carrier material of cellulose-based immobilized urease using microcrystalline cellulose (MCC) as raw materials was prepared by new hydrothermal oxidation synthesis method. The compositions and structure were characterized by IR, CP/MAS 13C NMR, XRD and SEM. The enzymatic characteristics of cellulose-based immobilized urease were tested and compared with chitosan-based immobilized urease and dialdehyde starch-based immobilized urease. The theoretical equations of enzymatic characteristics were established. The experimental results showed that DAC containing high aldehyde group content is prepared successfully using hydrothermal oxidation synthesis method. The dialdehyde cellulose-based immobilized urease had lower Michaelis constant, Km=0.0108 mol⋅L-1, better affinity ability, higher reusage and maintained enzyme activity within pH=5.0~9.0 regions compared with chitosan-based immobilized urease and dialdehyde starch-based immobilized urease. The theoretical equations were well able to characterize the enzymatic characteristics.