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投稿时间：2022-03-16
投稿时间：2022-03-16
中文摘要: 为获得可高效生产褐藻寡糖的褐藻胶裂解酶，该文筛选出一种来源于Microbulbifer salipaludis的褐藻胶裂解酶（Microbulbifer salipaludis alginate lyase，Misa-aly），并在大肠杆菌 Escherichia coli BL21（DE3）异源表达，分离纯化后进行酶学性质鉴定。结果表明，该酶最适pH值为8.5（Tris-HCl缓冲液），最适温度为45℃，偏好底物为聚甘露糖醛酸，40℃下保温1 h酶活下降约50%。Misa-aly对Na+依赖性较低，以海藻酸钠为底物通过3，5-二硝基水杨酸（3，5-dinitrosalicylic acid，DNS）法测定酶活为（53.0±1.2）U/mg，反应产物是聚合度为2～4的寡糖，24 h后酶解转化率达到94.7%，底物海藻酸钠几乎全部酶解。
Abstract:This study aimed to obtain a novel alginate lyase which could efficiently produce alginate oligosaccharides.The alginate lyase from Microbulbifer salipaludis（Misa-aly）was screened and overexpressed in Escherichia coli BL21（DE3）.After purification，the Misa-aly was characterized.The results showed that Misa-aly displayed the maximum activity at pH 8.5（Tris-HCl buffer）and 45 ℃，with a substrate preference to poly-mannuronic acid（polyM）.Misa-aly showed the residual activity of about 50% after being incubated at 40 ℃for 1 h and had low dependence on Na+.With sodium alginate as the substrate，the enzyme showed the activity of（53.0±1.2）U/mg，which was determined by the 3，5-dinitrosalicylic acid（DNS）method.The reaction products were oligosaccharides with a polymerization degree of 2 to 4.After incubation with Misa-aly for 24 h，most of the sodium alginate was degraded，and the conversion rate reached 94.7%.
keywords: alginate oligosaccharides alginate alginate lyase enzymatic characterization bioproduction
文章编号：202211003 中图分类号： 文献标志码：
基金项目:国家自然科学基金优秀青年基金（31922073）；中国博士后科学基金面上资助（2020M671979）；山东省博士后创新项目（202001018）
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