| Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads |
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| 作者姓名： | 梁足培 冯亚青 孟舒献 张卫红 |
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| 作者单位： | SchoolofChemicalEngineeringandTechnology,TianjinUniversity,Tianjin300072,China |
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| 基金项目： | SupportedbyNaturalScienceFoundationofTianjin(No.033802011). |
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| 摘 要： | The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant Kr, was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d.
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| 关 键 词： | 戊二醛 壳聚糖 微波放射技术 脲酶 化学特征 碳氧化物 |
Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads |
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| LIANG Zupei,FENG Yaqing,Meng Shuxian,ZHANG Weihong.Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads[J].Transactions of Tianjin University,2005,11(2):79-84. |
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| Authors: | LIANG Zupei FENG Yaqing Meng Shuxian ZHANG Weihong |
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| Institution: | School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China |
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| Abstract: | The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60 ℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant K m was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d. |
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| Keywords: | urease immobilization chitosan glutaraldehyde bead microwave |
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