固定化酶生产低乳糖牛乳的研究

Production of Low-lactose Milk with Immobilized Enzyme

以离子交换树脂D151为载体,采用吸附交联法固定化黑曲霉来源乳糖酶,并将固定化酶装填于填充床反应器中处理牛乳,研究固定化酶连续生产低乳糖乳的条件和使用稳定性。试验结果表明:在50℃下,牛乳以0.53mL/min的流速通过反应器生产低乳糖乳效果最好,可获得79.7%的乳糖水解率,达到低乳糖乳的要求。固定化酶在最适条件下连续水解牛乳,每隔20h用pH6.5缓冲液清洗反应柱,其10d内酶活力丧失12%,此时乳糖水解率为70.1%,达到低乳糖乳的要求。固定化乳糖酶连续使用半衰期约为22d。该研究为工业化利用固定化酶连续生产低乳糖乳提供了技术依据。

The lactase fiom Aspergillus niger was immobilized on the carrier of Kation-exchange resin D151 by absorption and crosslinking. The continuous production conditions of low-lactose milk and the usage stability of the immobilized lactase in the filled-bed reactor were researched. Result showed that, for continuous production of low-lactose milk in the filled-bed reactor, the best velocity and reaction temperature were 0.53 mL/min and 50 ℃, respectively, under which the hydrolysis rate of lactose reached 79.7%, meeting the request of low-lactose milk production. After a 10-day continuous operation of the column packed with immobilized enzyme under the best conditions and a wash of the column using buffer （pH6.5） per 20 h, 12% of initial enzyme activity was lost and the hydrolysis rate of lactose was 70.1%. The half-life of immobilized enzyme was about 22 days. This research provided the technical foundation for the industrial continuous production of low-lactose milk by immobilized lactase.