Preparation of Cu(II) adsorbed chitosan beads for catalase immobilization
Preparation of Cu(II) adsorbed chitosan beads for catalase immobilization
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DOI：
10.1016/j.foodchem.2008.10.049
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发表时间：
2009-06-01
期刊：
影响因子：
8.8
通讯作者：
Saraydin, Dursun
中科院分区：
文献类型：
--
作者：
Cetinus, Senay Akkus;Sahin, Ebru;Saraydin, Dursun
戊二醛预处理的交联壳聚糖珠（Ch）用于Cu（II）吸附（Cu-Ch）。用原子吸收光谱法测定了铜的吸附量，并在20 ℃下用间歇吸附法研究了壳聚糖对铜的吸附。在吸附实验中，发现一个Langmiur型（L）的Giles分类系统的吸附。采用Langmiur线性化方法计算了壳聚糖/铜体系的初始结合常数（Ki）、平衡常数（K）、单分子层空隙率（n）、位点大小（u）、最大占有率（o）和吸附自由能（AG）等结合参数。对固定化过氧化氢酶的温度活性曲线、热稳定性、操作稳定性和贮存稳定性等特性进行了评价。其中Cu-Ch-CAT和Ch-CAT的最适温度分别为25-35 ℃和35 ℃。表观Km值为18 mM，而在35 ℃下，壳聚糖珠上固定的过氧化氢酶（Ch-CAT）的Vmax计算为4800 μ mol（mg蛋白质/min）（-1）。在35 ℃下，吸附Cu（II）的壳聚糖珠上固定化过氧化氢酶（Cu-Ch-CAT）的表观Km值为53 mM，Vmax值为18450 μ mol（mg蛋白质/min）（-1）。Cu-Ch-CAT的操作稳定性、热稳定性和储存稳定性均高于Ch-CAT。(C)2008爱思唯尔有限公司保留所有权利。
Glutaraldehyde pretreated crosslinked chitosan beads (Ch) were used for Cu(II) adsorption (Cu-Ch). The amount of adsorbed copper was determined using atomic absorption spectroscopy.Adsorption of the copper onto the chitosan was studied batch adsorption technique at 20 degrees C. In adsorption experiments a Langmiur type (L) adsorption was found with respect to the Giles classification system. Binding parameters such as initial binding constant (Ki), equilibrium constant (K), monolayer covarege (n), site-size (u), maximum fractional occupancy (o) and free energy of adsorption (AG) for the chitosan/copper system were calculated Langmiur linearization method.Glutaraldehyde pretreated crosslinked chitosan beads (with and without copper) were used in catalase (CAT) immobilization. Various characteristics of immobilized catalase such as, the temperature activity curve, thermal stability, operational stability, and storage stability were evaluated. Among them optimum temperature were found to be 25-35 degrees C and 35 degrees C for Cu-Ch-CAT, Ch-CAT, respectively. The apparent Km value was 18 mM whereas the Vmax was calculated as 4800 mu mol (mg protein min)(-1) for immobilized catalase on chitosan beads (Ch-CAT) at 35 degrees C. The apparent Km value was 53 mM and the Vmax value was 18450 mu mol (mg protein min)(-1) for immobilized catalase on Cu(II) adsorbed chitosan beads (Cu-Ch-CAT) at 35 degrees C. Operational, thermal and storage stabilities of the Cu-Ch-CAT were higher than that of Ch-CAT. This study demonstrated that the potential of cross-linked chitosan beads applied to metal sorption and enzyme immobilization. (C) 2008 Elsevier Ltd. All rights reserved.