羧甲基纤维素-壳聚糖聚电解质复合物对乳糖酶的固定化研究  

Immobilization of β-Galactosidase on Carboxymethyl Cellulose-chitosan Polyelectrolyte Complex

作　　者：张锐[1] 陈振宁[2] 方桂珍[1] 马英梅[1] 戴晓峰[1] 

机构地区：[1]东北林业大学材料学院,黑龙江哈尔滨150040 [2]哈尔滨工业大学理学院,黑龙江哈尔滨150001

出　　处：《林产化学与工业》2009年第B10期138-142,148,共6页Chemistry and Industry of Forest Products

基　　金：高等学校博士学科点专项科研基金资助项目(20060225008);东北林业大学研究生科技创新项目(无编号)

摘　　要：以羧甲基纤维素-壳聚糖聚电解质复合物为载体,戊二醛为交联剂,制备了固定化乳糖酶,优化了固定化条件,分析了固定化酶的性能。结果表明:向0.5 g羧甲基纤维-壳聚糖聚电解质复合物中,加入质量浓度为1 g/L的酶液2 mL,固定9 h;再加入体积分数为0.5%的戊二醛,交联3 h时,固定化效果最好,酶活力为0.023 5 U/g;固定化酶最适反应温度50℃,pH值为7,游离酶的最适温度为30℃,pH值为9;固定化酶的pH值稳定性优于游离酶,热稳定性低于游离酶;重复使用3次时,稳定性较好;固定化米氏常数(Km)为0.705 1 mmol/L,较游离酶有所减小,表明底物与固定化酶亲和力增加,利于酶促反应进行。β-Galactosidase was immobilized on carboxymethyl collulose-chitosan （CMC-CS） polyelectrolyte complex with glutaraldehyde by crosslinking reaction. The immobilization conditions and characterization of the immobilized enzyme were studied. The results indicated that the optimal activity was 0.023 5 U/g, when the concentrantion of glutaraldehyde was 0.5 %, dosage of β-galactosidase was 1 g/L per 0.5 g CMC-CS, immobilization time and crosslinking time were 9 and 3 h, respectively. The optimal- reaction temperature and pH value of the immobilized enzyme were 50 ℃ and 7, respectively ; and those of free enzyme were 30 ℃ and 9, respectively. The immobilized enzyme showed lower thermal stability than that of the free enzyme, because of irreversible reaction from carrier and enzyme, but pH value stability of the immobilized enzyme were better than that of the free enzyme. The immobilized β-gatactosidase showed high stability when it was used repeatedly for three times. Michaelis constant （Km） of the immobilized enzyme was 0.705 1 mmol/L, which was higher than that of the free enzyme, which indicated the increased affinity of immobilized enzyme toward substrate which was beneficial to the enzymatic reaction.

关 键 词：羧甲基纤维素 壳聚糖 聚电解质复合物 乳糖酶 固定化 

分 类 号：TQ351[化学工程] O636[理学—高分子化学]