Immobilization of Candida antarctica lipase B by adsorption to green coconut fiber
Immobilization of Candida antarctica lipase B by adsorption to green coconut fiber
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DOI：
10.1007/s12010-007-8072-4
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发表时间：
2008-03-01
影响因子：
3
通讯作者：
Goncalves, Luciana R. B.
中科院分区：
文献类型：
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作者：
Brigida, Ana I. S.;Pinheiro, Alvaro D. T.;Goncalves, Luciana R. B.
以绿色椰壳纤维为载体，采用物理吸附法固定化厌氧假丝酵母B型脂肪酶（CALB）。研究了接触时间、固定化酶用量、固定化酶溶液pH值等因素对固定化酶活力的影响，确定了合适的固定化方法。测定了可溶性和固定化脂肪酶的动力学常数。测定了椰子纤维与酶溶液接触2小时后获得的固定化酶的热稳定性和操作稳定性，所述酶溶液在25 mM磷酸钠缓冲液pH 7中含有40 U/ml。通过吸附在椰子纤维上的CALB固定化促进了在50和60 ℃下热稳定性的增加，因为固定化酶的半衰期（t（1/2））分别是可溶性酶的2倍和92倍。并对丁酸甲酯水解反应和丁酸丁酯合成反应的操作稳定性进行了评价。在丁酸甲酯水解的第三个循环后，它保留了不到50%的初始活性，而Novozyme 435在第十个循环后保留了70%以上。然而，在丁酸丁酯的合成中，与Novozyme 435相比，固定化在椰子纤维上的CALB显示出良好的操作稳定性，在第六个反应循环后保持其初始活性的80%。
An agroindustrial residue, green coconut fiber, was evaluated as support for immobilization of Candida antarctica type B (CALB) lipase by physical adsorption. The influence of several parameters, such as contact time, amount of enzyme offered to immobilization, and pH of lipase solution was analyzed to select a suitable immobilization protocol. Kinetic constants of soluble and immobilized lipases were assayed. Thermal and operational stability of the immobilized enzyme, obtained after 2 h of contact between coconut fiber and enzyme solution, containing 40 U/ml in 25 mM sodium phosphate buffer pH 7, were determined. CALB immobilization by adsorption on coconut fiber promoted an increase in thermal stability at 50 and 60 degrees C, as half-lives (t(1/2)) of the immobilized enzyme were, respectively, 2- and 92-fold higher than the ones for soluble enzyme. Furthermore, operational stabilities of methyl butyrate hydrolysis and butyl butyrate synthesis were evaluated. After the third cycle of methyl butyrate hydrolysis, it retained less than 50% of the initial activity, while Novozyme 435 retained more than 70% after the tenth cycle. However, in the synthesis of butyl butyrate, CALB immobilized on coconut fiber showed a good operational stability when compared to Novozyme 435, retaining 80% of its initial activity after the sixth cycle of reaction.