α-葡聚糖酶已经在用于甘蔗糖、甜菜糖以及精练糖生产中，其使用环境与一般酶学性质研究时选取的条件具有明显差异。本文结合实际生产条件，通过提前升温加热，调整pH，加入蔗糖到反应底物溶液中来模拟炼糖生产环境，再测定α-葡聚糖酶在不同条件下的活性变化，为生产应用提供数据支撑。在无机盐缓冲体系中，温度的升高和中性到碱性的pH对α-葡聚糖酶的活性影响明显。在55 ℃，pH 5.5~7.0水浴15 min后，剩余酶活保持在20%到40%的区间。当蔗糖加入反应溶液后，α-葡聚糖酶对温度和pH的适应性会明显提高。当蔗糖浓度达到60 °Bx时，α-葡聚糖酶在65 ℃，pH 5.5~8.0或者75 ℃，pH 5.5~7.0的条件下，水浴15 min后剩余酶活均可保持40%以上。这说明α-葡聚糖酶在高浓度蔗糖溶液中，热稳定性良好，可以应用在炼糖生产当中。

Dextranase (EC 3.2.1.11) has been used in the production of cane sugar, beet sugar and refined sugar. There were obvious differences between the conditions of using this enzyme and those normally used for studies on general enzymatic properties. In this study, we simulated sugar refining conditions by preheating, pH adjustment and adding sucrose to the reaction substrate solution according to the actual production conditions, and then measured the activity changes in the activity of dextranase under different conditions. The obtained results the data will be provided data to support for the sugar refining production. The experimental results showed that, it’s obvious that the effect of temperature and pH on enzyme in the inorganic salt buffer. In the inorganic salt buffer system, the increase in temperature and use of a neutral to alkaline pH had a significant effect on the activity of dextranase. At 85 ℃, pH 5.5~7.0, the enzyme activity remained between 20% to 40%. When sucrose was added after an incubation in the water bath at 55 ℃ and pH 5.5~7.0 for 15 min, the remaining enzyme activity was in the range of 20% to 40%. Upon the addition of sucrose to the reaction solution, the adaptability of the dextranase to temperature and pH was remarkably improved. So this dextranase can be used in manufacture. In the 60 °Brix sucrose solution, when the dextranase was at 85 ℃, pH 5.5~7.0 or 75 pH 5.5~8.0, the activity after 15 min could be maintained over 40%. When the sucrose concentration was at 60 °Brix, no less than 40% of the activity of dextranase was retained after a reaction for 15 min in the water bath at 65 ℃ and pH 5.5~8.0 or 75 ℃ and pH 5.5~7.0. These results indicate that dextranase has good thermal stability in a high-concentration sucrose solution and can be used in sugar refining.

广东省酶制剂与生物催化工程技术研究中心项目；广西科技计划项目(桂科AB16380099)