纤维素酶固定化研究

Studies on Properties of Immobilized Cellulase on a Carrier

采用交联法制备了聚乙二醇改性壳聚糖(PEG-CS)载体,并将其用于固定纤维素酶.探讨了载体制备过程中的几种主要影响因素、纤维素酶固定化的影响因素,并对固定化纤维素酶的性质进行了讨论.结果表明,固定化酶最适pH值比原酶降低,最适温度为60℃,比游离酶高10℃.在pH值为5.0,温度40℃时,固定化酶对羧甲基纤维素钠盐的表观米氏常数为7.2 mg/L,而游离酶为3.3 mg/L.与游离酶相比,该固定化纤维素酶热稳定性明显提高,并具有良好的操作和存储稳定性.

PEG- CS（ chitosan modified by polyethylene glycol） was prepared and applied to immobilize cellu- lase. ＇lhe immobilization conditions and properties of the immobilized enzyme on PEG - CS were studied. The immobilized enzyme exhibits the maximal activity at pH 4. 0. The optimal temperature of immobilized enzyme is at 60~, higher than free eellulase. In acetic acid-sodium-acetate buffer（ pH 5.0, 40℃ ）, the Km for CMCNa of immobilized cellulase and free cellulase are separately 7.2mg/L and 3.3mg/L, so the affinity of cellulase decreases after being immobilized. The thermal-, operational-, and storage-stabilities of the immobilized enzyme are obviously increased compared to those of the free one.