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机构地区:[1]合肥工业大学生物与食品工程学院,安徽合肥230009
出 处:《食品科学》2007年第12期254-257,共4页Food Science
基 金:安徽省自然科学基金项目(050410301);合肥工业大学科学发展基金项目(053001F)
摘 要:交联酶聚集体法是一种新型的无载体酶固定化方法。本实验用该法固定化黑曲霉β-葡萄糖苷酶,对其制备条件、结构特征、酶学性质进行了研究。结果表明,β-葡萄糖苷酶酶液在冰水浴中经90%的硫酸铵沉淀30min后,以5%戊二醛水溶液进行酶聚集体交联反应,可获得较高活性的交联酶聚集体,酶活回收率达75%,对对-硝基苯基-β-D-葡萄糖苷作用的最适温度、最适pH值和Km值分别为60℃、pH4.0和4.61×10-3mol/L,与游离酶相比,表现更高的底物亲和力。将其用于大豆异黄酮活性苷元染料木素的合成,40min内对染料木苷转化率达到66%。Abstract: Cross-linked enzyme aggregates (CLEAs) were used to immobilize β-glucosidase from Aspergillus niger. β- glucosidase was precipitated by 90% ammonium sulfate solution for 30 min at 0 ℃, then the aggregates were cross-linked by 5% glutaraldehyde solution. The obtained cross-linked β-glucosidase aggregates remained 75% of total enzyme activity. Its optimum reaction temperature, reaction pH and Km to pNPG were 60 ℃, 4.0 and 4.61 × 10^-3 mol/L, respectively. Compared to the free β-glucosidase, the cross-linked ~glucosidase aggregates had higher affinity to the substrate. The conversion rate was 66% when cross-linked β-glucosidase aggregates were employed to genistein production from soybean isoflavone genistin in 40 min.
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