乳糖酶和酿酒酵母的共固定化及其在乳清发酵中的应用

Co-immobilization and application of lactase and Saccharomyccs cerevisiae in whey fermentation

利用凹凸棒土的强吸附作用,首先将乳糖酶吸附于凹凸棒土上,再采用壳聚糖溶液包埋的方法制成乳糖酶与酿酒酵母细胞的共固定化凝胶颗粒。实验结果表明,凹凸棒土与壳聚糖的适宜比例为5:1,加酶量为300u/g凹凸棒土,室温下吸附时间为4h:所制得的共固定化酶-酵母细胞发酵乳糖的适宜pH值和温度分别为6.0和32℃,乳糖浓度13%～15%:在适宜的发酵条件下,以20%的乳清(乳糖含量为13.42%)为底物发酵30h,酒精浓度达8.3%(v/v),乳糖转化率达93.2%。

The lactase was absorbed on attapulgite and co-entrapped with Saccharomyces cerevisiae by chitosan solution to making co-immobilized gel particles. The immobilization conditions and characterization of the co-immobilized lactase-S, cerevisiae were studied. The results showed that the ratio of attapulgite to chitosan was 5：1, the optimum load of lactase was 300 u/g （attapulgite） and the absorption time is 4 h. The optimal technical conditions were as follows： temperature at 28℃, pH value as 4.9 and lactose concentration was 13%-15%, Under such conditions, with 20% whey （lactose concentration was 13.42%） as the substrate, the alcohol yield could reach 8.3%（v/v） and the utilization ratio of lactose was 93.2% after 30 h fermentation with the co-immobilized lactase-S, cerevisiae.