氨基化细菌纤维素载体的制备及其固定β-半乳糖苷酶

Preparation of bacterial cellulose membrane with amino group as carrier and its immobilization of β-galactosidase

利用二氯亚砜和乙二胺对细菌纤维素薄膜进行氯化和氨基化制备氨基化细菌纤维素薄膜,并以该薄膜作为载体固定β-半乳糖苷酶,研究载体的结构性质和固定化酶的制备条件及相关酶学性质。通过元素分析、红外光谱和X线光电子能谱等分析方法来表征载体性质。结果显示,有大量氨基接入细菌纤维素表面。最佳的固定化酶的条件:戊二醛添加量4 g/L,固定化时间3 h,酶添加量3 mg/m L,p H7.0和交联时间90 min,此条件下,最高酶活回收率为78.4%,吸附酶量为63.1 mg/g。与游离酶相比,固定化酶的最适温度为40℃,比游离酶高10℃,最适p H提高0.5,有向碱性方向移动的趋势,重复使用7次后剩余77.8%的相对酶活力。

Sulfoxide chloride and ethylenediamine were used to conduct the chlorination and amination of bacterial cellulose for the immobilization of β-galactosidase. Immobilization conditions, the enzymatic properties and microstructure of immobilized β-galactosidase were studied. Elemental analysis, infrared spectrum and X-ray photoelectron spectroscopy confirmed the presence of abundant amino groups on the surface of bacterial cellulose. Results showed that the maximum recovery of enzyme activity and the amount of immobilized fl-galactosidase were 78.4% and 63.1 rag/g, respectively, under the optimal immobilization conditions： glutaraldehyde concentration 4 g/L, immobilization time 4 h and enzyme concentration 3 mg/mL, pH 7.0 and crosslinking time 90 rain. Compared with the free β-galactosidase, the optimal reaction temperature was increased from 30 to 40 ℃ , and the optimal pH increased by 0. 5. In addition, the immobilized β-galactosidase remained 77.8% of its original activity after its 7th repeated use.