固定化亚油酸异构酶制备及其性质

以海藻酸钠、壳聚糖为载体，分别采用直接包埋、交联-包埋法制备固定化亚油酸异构酶；研究酶的固定化条件和固定化酶的部分性质。结果表明：以海藻酸钠为载体，采用交联-包埋法以戊二醛为交联剂时固定化效果较好；最佳固定化条件为：海藻酸钠质量浓度为3g/100mL，戊二醛质量浓度为0.3g/100mL，CaCl2质量浓度为2g/100mL；固定化酶的最适反应温度为50℃，最适反应pH值为5.0；与游离酶相比，固定化酶的热稳定性显著提高，温度在20～60℃之间较稳定，pH值在2～8之间表现出较好的酸碱耐受性；固定化亚油酸异构酶的Km为0.36mg/mL。连续操作6次固定化相对酶活力仍保持70.6%，与游离酶相比，固定化亚油酸异构酶催化效率约提高了50%。

Preparation and Properties of Immobilized Linoleate Isomerase

Sodium alginate and chitosan were used as the carriers for immobilizing linoleate isomerase by entrapment and crosslinking entrapment methods.The immobilization conditions of linoleate isomerase and properties of immobilized linoleate isomerase were investigated.The results indicated that the optimal conditions for immobilizing linoleate isomerase were 3 g/100 mL sodium alginate,2 g/100 mL CaCl2and 0.3 g/100 mL glutaraldehyde.The optimal temperature and pH for the conversion of linoleic acid(LA) to conjugated linoleic acid(CLA) were 50 ℃ and 5.0,respectively.The thermal and pH stabilities of immobilized linoleate iosmerase were better than those of native enzyme in the range of 20-60 ℃ and pH 2-8.The Kmof immobilized linoleate iosmerase was 0.36 mg/mL.After sixth repeated use,the immobilized enzyme remained 70.6% of its original activity.It could increase CLA production by 50% when compared with native linoleate isomerase.