介孔分子筛MCM-41固定糖化酶的研究

以介孔分子筛MCM-41为载体、戊二醛为交联剂,对糖化酶进行了固定化.考察了固定化温度和时间、给酶量、pH值以及戊二醛浓度等因素对固定化效果的影响,并对固定化酶的酶学性质进行了研究.结果表明,糖化酶最佳固定化条件是:酶与载体比例为50mg/g、固定化温度20℃、固定化时间8h、pH值6.1、戊二醛浓度7.5％,此条件下固定化酶的相对酶活力为47％.固定化酶的最适作用温度和最适作用pH值没有改变,同游离酶一样,分别为60℃和4.6,米氏常数Km由原来的0.031 mol/L降为0.018mol/L.     

介孔分子筛MCM-41固定化胰蛋白酶的研究

以介孔分子筛MCM-41作为载体,戊二醛作为交联剂,对胰蛋白酶进行了固定化。研究了固定化条件对酶活及酶活性回收率的影响,并对固定化酶的热稳定性和操作稳定性做了探讨。结果表明,当每克载体的给酶量为30mg,固定化温度15℃,固定化时间3h,pH8.0,戊二醛体积分数0.4%时,胰蛋白酶的固定化效果最好,此时平均酶活性回收率达60%左右。固定化酶的热稳定性与游离酶相比有了显著的提高,并且固定化酶具有较好的操作稳定性,连续反应10批后,酶剩余活性仍保持在80%以上。      

介孔材料SBA-15固定化胰蛋白酶的研究

在酸性条件下以正硅酸乙酯(TEOS)为硅源、非离子表面活性剂Pluronic P123为模板剂合成了介孔分子筛SBA-15,将其作为载体,对胰蛋白酶进行了固定化研究.研究了固定化条件对固定化酶量的影响,以及固定化酶的热稳定性和操作稳定性.结果表明,当酶液浓度大于5 mg/mL,固定化时间10 h时,胰蛋白酶的固定化效果最好,固定化酶量可达23.6 mg/g.固定化酶的热稳定性与游离酶相比有了显著的提高,且固定化酶具有较好的操作稳定性,连续反应6批次后,酶的剩余活性仍保持在40 %以上.     

介孔分子筛MCM-48固定化木瓜蛋白酶性质的研究

以介孔分子筛MCM48为载体、戊二醛作交联剂对木瓜蛋白酶进行了固定化。实验结果表明,与游离酶相比,固定化酶的热稳定性有了显著的提高,其半衰期达到了2500min以上,是游离酶(80min)的30倍以上。固定化酶的pH稳定性和储藏稳定性也有了明显改善。此外,固定化酶还具有很好的操作稳定性,经过12d的连续酶解,酶活力仍保持在初始酶活力的70%以上。     

胰蛋白酶在磁性核壳介孔分子筛上的固定化研究

采用吸附法研究胰蛋白酶在磁性核壳介孔分子筛(Fe3O4@MCM-41)上的固定化过程。考察吸附条件对胰蛋白酶固定化性能的影响,并对固定化酶的酶学性能、载体结构等进行表征。结果表明：在固定化时间为4h、胰蛋白酶给酶量为60mg/g、pH8.2的条件下,固定化酶活回收率可达55.9%。表面能谱分析(EDS)结果表明,固定化酶中酶含量(以含氮量计)约为14%,与游离酶相比,固定化酶的耐温区间、pH值适应范围明显变宽,并具有一定的可重复操作性,且固定后载体仍然保持良好的介孔结构。     

介孔分子筛搭载槲皮素食品抗氧化活性包装膜制备及其性能研究

以十六烷基三甲基溴化铵(CTAB)和聚(乙二醇)-block-聚(丙二醇)-block-聚(乙二醇)Mn~2900(P131345)作为双模板剂制备出纳米二氧化硅介孔分子筛MCM-41(Mobil Composition of Matter No.41),并进一步以此为载体搭载天然抗氧化剂槲皮素,以低密度聚乙烯(LDPE)为基材制备了一种食品抗氧化活性包装膜。结果表明,所制备纳米二氧化硅介孔分子筛MCM-41比表面积为439.173 m²/g,孔体积为0.665 cm³ g^-1,孔径分布为2.4、4.0 nm。吸附槲皮素后,其1,1-二苯基-2-三硝基苯肼(DPPH)自由基在经过24 h和1200 h后平均清除率分别为56.75%和66.01%。同时,槲皮素在食品模拟物中的扩散速率D(cm²/s)由2.127×10^-13下降到3.089×10^-14。表明以介孔分子筛为载体制备的食品抗氧化活性包装膜具备抗氧化的作用并具备缓释性。     

SBA-15固定化酶的研究进展

该文综述介孔材料SBA-15固定化酶的研究进展,介绍固定化方法包括物理吸附法、包埋法、共价结合法和交联法的特点。同时结合近年来国内外的研究现状,归纳SBA-15固定化酶在制备生物基化学物质、生物传感器、环境保护中的应用。最后展望SBA-15固定化酶的应用前景,未来可在固定化酶载体和技术上深入研究,进一步推进SBA-15固定化酶在工业中的实际应用。     

载银介孔SBA-15抗菌剂的制备及表征

为解决有机抗菌剂耐热性差、易分解和使用寿命短的问题,选用介孔无机材料SBA-15作为载体,以γ-氨丙基三乙氧基硅烷(APTES)为修饰剂,采用嫁接的方法对介孔SBA-15进行改性,使其表面接枝氨基官能团,采用常规AgNO3溶液浸渍法,制得抗菌性能优良、杀菌效果持久的广谱抗菌剂.通过x射线衍射(XRD)、红外光谱(FT-...     

介孔分子筛对吡虫啉的吸附性能及其对纸张性能的影响

利用介孔分子筛的吸附作用,以分子筛作为防白蚁药物吡虫啉载体,将分子筛以填料加入到纸张中。实验结果表明:分子筛对吡虫啉有着明显的吸附作用,通过六烷基三甲基氯化铵(CTAC)的增溶能够增加分子筛对吡虫啉的吸附作用;分子筛的加入对纸张强度有着负面的影响,但又能提高纸张的光学性能;吸附了吡虫啉的分子筛加入纸张后,纸张具有良好的抗白蚁效果。     

固定化糖化酶的研究

文中就糖化酶的固定化固定化酶的性质作了初步研究,利用明胶和海藻酸钠的聚合作用与海藻酸钙凝胶球的包埋作用制备定化糖化酶,结果表明：固定化酶米氏常数Km为12．3mg/ml,游离酶米氏常数Km为7.5mg/ml,固定化酶最适温度为70℃,游离酶为60℃,同时固定化酶明显提高了游离酶的耐热性,储藏稳定性和操作稳定性。     

Immobilization of Glucoamylase on Cellulose

The effectiveness of immobilization of glucoamylase on cotton linters and beech wood pulp activated in a number of manners was examined as well as the kinetic properties of immobilized enzyme.     

Immobilization of Glucoamylase on Activated Aluminiumoxide

The adsorption capacity of glucoamylase on unactivated, γ-irradiation activated and transition metal alumina as well as the catalytic activity and stability of immobilized enzyme were studied.     

Immobilization of Glucoamylase on Silanized Aluminium Oxide

The possibility of immobilization of glucoamylase (GA) on silanized Al₂O₃ was examined using adsorption and covalent bonding via glutaric aldehyde. Both methods yield active unsoluble enzymes, which however gradually lose their catalitic activity in cyclic operation. Various agents aiming to improve the stability of immobilized GA were tested. It has beer found that the enzyme bound covalently to the carrier retains its activity to the higher degree while kept in the substrate solution.     

糖化酶的固定化研究进展

综述了国内外糖化酶固定化的研究进展 ,并讨论了利用超滤膜反应器研究糖化工艺连续性的前景     

Immobilization of Aspergillus niger Mycelium on Seeds for Glucoamylase Production

Mycelium of the glucoamylolytic mutant Aspergillus niger C-58-III was immobilized on wheat, rye, barley, pea, buckwheat and mustard seeds in repeated-batch flasks. After every 24th it was possible to obtain culture broth rich in glucoamylase. The highest yield of enzyme (66.4 U × ml⁻¹) was obtained on the mustard carrier. Immobilized cells were successfully reused with high level of enzyme formation being mantained for longer period (192h). Some of the variables influencing the enzymatic activity have been standardized. Enzyme productivity reached in immobilized cells of A. niger was 1.6-times higher in comparison with free cells.     

Improved Glucoamylase Immobilization onto Calcined Chicken Bone Particles

Calcination was considered for the first time as an alternative to recover inorganic bone component from spent glucoamylase-bone derivatives. The subsequent adsorption of glucoamylase (GA) onto calcined bone particles was assessed. Adsorption capacity of the calcined matrix was found to be from 1.1- to 1.4-fold superior to that of non-calcined supports, and it was dependent on the applied load. Moreover, the expressed activity of GA derivatives on calcined matrix was, at least, 2-fold higher than that of biocatalysts onto non-calcined support. The optimization of the loading allowed the preparation of derivatives with 139 GA units per gram of support, which preserve 52% of the immobilized activity. Additionally, calcination of spent GA biocatalysts on calcined bone particles was performed, and adsorption of glucoamylase onto the bone particles calcined a second time was also found to be efficient. In addition to the improved catalytic properties, the half-life at 55°C of the GA biocatalysts on calcined bone was increased 1.7-fold in comparison with that of soluble GA and GA adsorbed onto non-calcined bone particles. Furthermore, the same cassava starch conversion can be achieved batchwise in a stirred-tank reactor using less insoluble biocatalyst, 37% of the GA-bone derivative, which represents an important saving for industrial applications.