以双醛氧化纤维素为载体固定化β-半乳糖苷酶,研究了固定化酶的制备条件、微观结构及酶学性质,结果表明:固定化时间为4 h,[酶]/[载体]=1:15(g:g)时,固定化酶的活力最高为0.517 U/g。红外光谱和扫描电镜对固定化酶的微观结构研究表明,双醛氧化纤维素的醛基与β-半乳糖苷酶的氨基发生共价反应形成固定化酶。与游离酶相比,β-半乳糖苷酶经过固定化后热稳定性和耐酸碱性增强,米式方程分析表明,β-半乳糖苷酶经固定化后与底物的亲和力降低,固定化酶重复使用5次后,相对酶活力为63%。

Dialdehyde oxycellulose was prepared as carrier to immobilize the β-galactosidase.The preparation conditions,microstructure and enzymatic properties of the immobilized enzyme were studied.The results showed that the maximum activity of immobilized enzyme is 0.517U/g when immobilized time is 4h,[enzyme]∶[carrier] =1∶15(g∶g).The microstructure of immobilized enzyme,which was studied with infrared spectrum and scanning electron microscope analysis,showed that the aldehyde group of dialdehyde oxycellulose could react with the amino group of the β-galactosidase to form immobilized enzyme.Compared with free enzyme,the heat stability and acid as well as basic resistance of immobilized β-galactosidase were increased;the decrease of the affinity with substance of dialdehyde oxycellulose immobilized β-galactosidase was demonstrated by michaelis equation analysis.After reuse for five times,the relative enzyme activity of immobilized enzyme was 63%.