用吸附法固定脂肪酶时,膜材料的亲疏水性对固定化酶的量、比活力和活力稳定性等有很大影响.今以柱状假丝酵母脂肪酶和猪胰脂肪酶为研究对象,选取了8种亲疏水性不同的膜材料（醋酸纤维素、聚丙烯腈、聚酰胺、聚砜、聚醚砜、聚偏二氟乙烯、聚丙烯和聚四氟乙烯）作为固定化载体,用吸附法制备了固定化脂肪酶膜.研究结果表明,强疏水性聚四氟乙烯和聚丙烯膜对两种酶的吸附量都比较大,且固定化酶的比活力和活力回收率比较高,聚四氟乙烯固定化柱状假丝酵母酶比游离态酶的半衰期提高了6倍以上.强亲水性醋酸纤维素膜对猪胰脂肪酶的吸附量比聚四氟乙烯高,但是固定化酶的比活力、活力回收率比强疏水性膜低,而接触角在40°～50°的聚酰胺膜和聚砜膜的吸附量最小.因此吸附法制备固定化脂肪酶膜,选择聚丙烯膜和聚四氟乙烯膜是合适的,制备的优化条件为吸附温度25℃,酶溶液的pH为7.5,吸附时间10 h.
Three kinds of support for enzyme immobilization were prepared by modifying SBA-15 mesoporous silica with thiol,methyl and hexyl groups respectively.The prepared supports were characterized with FT-IR and BET method and exhibited high specific surface area and uniform pore size.Furthermore,unmodified SBA-15 and the modified SBA-15 materials were used for lipase immobilization.The results were compared in terms of enzyme adsorption capacity,activity,activity retention and stability.The modified SBA-15 materials with thiols(SBA-15-PrSH)showed good performance for lipase immobilization.Compared with unmodified SBA-15,the adsorption capacity of SBA-15-PrSH to lipase was improved by more than 80%,and the activity retention increased by more than 10%.
