凹凸棒土—壳聚糖耦合固定化乳糖酶及其在低乳糖乳制备中的应用

采用凹凸棒土吸附与壳聚糖溶液包埋耦合的方法进行乳糖酶的固定化.结果表明,当凹凸棒土∶壳聚糖为5∶1、吸附时间为4 h、加酶量为260 U.g-1时,固定化酶活力达107.6 U.g-1、酶回收率为50.6%;所制得固定化乳糖酶的适宜温度和pH值分别为40~45℃及6.4~6.8;用固定化乳糖酶水解牛奶中的乳糖,在温度为45℃时间为1.5 h时乳糖水解率即达69.5%,38℃、3 h水解率为71.3%.

Co-immobilization of lactase and its application in production of low lactose milk

The lactase was co-immobilized by the method of coupling attapulgite absorption and chitosan solution embedding.The results showed that the activity and recovery rate of immobilized enzyme were 107.6 U·g-1 and 50.6 % respectively under the following conditions∶ ratio of tattapulgite to chitosan was 5∶1,amount of lactase was 260 U·g-1(attapulgite) and the absorption time was for 4 h.The optimal temperature and pH value for immobilized enzyme were 40～45 ℃ and 6.4～6.8.The immobilized lactase could hydrolyze 69.5 % lactose in milk at 45 ℃ for 1.5 h,and 71.3 % at 38 ℃ for 3 h.