共查询到18条相似文献,搜索用时 171 毫秒
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碳酸酐酶(Carbonic anhydrase, CA)是一种广泛存在于各种真核生物以及原核微生物中的含锌金属酶,可以高速催化CO2的可逆水合反应,但其成本昂贵,且易失活、难回收,因此实际应用受到了限制。酶的固定化技术不仅可以使酶像固体催化剂一样可回收再利用,还能提高酶的稳定性,保持其高催化性能。固定化酶具有一定的机械强度和形状,可置于反应床或连续反应器中生产,且反应过程可控。本研究以绿色环保、来源广泛的矿渣为原料,以NaOH为碱激发剂,通过悬浮分散固化法制备了地质聚合物微球并将其作为载体;以戊二醛为交联剂,使用吸附-交联法成功地将碳酸酐酶(Carbonic anhydrase, CA)固定在地质聚合物微球上。通过酶活回收率和相对酶活来评价碳酸酐酶的固定化效率,同时利用不同的表征手段对载体与固定化酶的微观形貌、结构变化等进行了对比分析。实验结果表明,碳酸酐酶在地质聚合物微球上的最佳固定化条件为pH值8.0、反应温度30℃、固定化时间2 h、载体用量100 mg、交联剂浓度0.2%(质量分数)、交联反应时间1 h。在此条件下的固定化碳酸酐酶的酶活回收率最高可达55.... 相似文献
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采用天然高分子聚合物甲壳素作载体,以戊二醛为交联剂,对蜗牛酶进行固定化。研究了酶量、戊二醛浓度、pH和溶剂对蜗牛酶固定化的影响。结果表明,0.5g甲壳素与0.8%的戊二醛交联后,与用双蒸水配制的pH为5.6的酶液混合制备的固定化酶活性最高。用优化条件下制备的固定化酶降解壳聚糖,先调pH为4.0,360min后调pH为4.8使得平均降解速率最大。当壳聚糖质量百分数为0.3%时,初始反应速率最大,并提出了新的经验模型描述壳聚糖的降解过程。用该固定化酶连续降解壳聚糖70d,酶活为原来的98%,降解性能保持稳定。 相似文献
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以碳包铁(Fe@C)纳米粉作为磁性内核,用海藻酸钠作表层高分子,以正庚烷为油相,AOT为表面活性剂,氯化钙、环氧氯丙烷作交联剂,通过反相微乳法制备出了碳包铁/海藻酸钠核壳微球,系统考察了海藻酸钠的浓度、交联剂用量等对所制复合纳米微球性质的影响,并对产物进行了初步的性能表征.结果表明,选择合适的海藻酸钠的浓度、交联剂用量和其它相关参数,可以制备出外观为球形、分散性好、平均粒径约为250nm、具有强磁响应性的复合微球. 相似文献
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载药壳聚糖缓释微球的制备及其释放研究 总被引:1,自引:0,他引:1
实验采用乳化交联法,使用复合交联剂(先用甲醛交联,再用戊二醛交联),制得盐酸四环素壳聚糖缓释微球,并考察不同分子量的壳聚糖、原料质量比、交联剂用量、复合交联剂用量、搅拌速度对微球的影响,筛选出最佳条件制备出戢药微球,并研究了该微球在扫描电镜和倒置式研究型显微镜下的形态及其在pH=7.4,温度为37℃时的释放规律.结果表明,采用复合交联剂的乳化交联法所制得的微球球形好,粒径分布为5~50μm之间,载药量为26.9%,包封率为56.3%,并且具有良好的缓释效果. 相似文献
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单宁微球固载α-淀粉酶及其催化性能 总被引:1,自引:0,他引:1
以单宁微球为载体,采用戊二醛交联法固定α-淀粉酶。探讨了最佳固定化条件,并考察了温度、pH值和淀粉初始浓度等对固定α-淀粉酶催化淀粉水解的影响。结果表明,单宁微球对α-淀粉酶的吸附率达到了96.99%。最佳固定条件为:戊二醛质量分数0.10%,pH5.5,温度25℃,时间2h。固定α-淀粉酶的重复5次后仍具有较好的催化效果。 相似文献
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Fe3O4/壳聚糖磁性微球功能化SBA-15介孔分子筛的合成 总被引:1,自引:0,他引:1
通过反相悬液交联法制备出了Fe3O4壳聚糖磁性微球,以3-丙胺基三乙氧基硅烷(APTES)为硅烷偶联剂,采用后修饰法得到硅烷化SBA-15介孔分子筛.以戊二醛为交联剂将Fe3O4壳聚糖磁性微球接枝在硅烷化SBA-15介孔分子筛上.运用X射线衍射、傅里叶红外光谱等手段对Fe3O4壳聚糖磁性微球(MCS)接枝后的硅烷化SBA-15介孔分子筛进行了表征.分析结果表明,Fe3O4壳聚糖磁性微球通过硅烷偶联剂以化学键形式结合在SBA-15介孔分子筛上. 相似文献
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以海藻酸钠和γ-氨丙基三乙氧基硅烷为原料,在一定条件下使二者发生交联反应生成复合水凝胶,并以此复合凝胶作为固定化纤维素酶的载体。纤维素酶的包埋率超过了85%, 酶固定前后的SEM图表明纤维素酶非常均匀地分布在载体中。探讨了pH、 温度对固定化酶和游离酶活力的影响, 结果表明固定化酶具有对pH和温度更高的稳定性, 固定化酶的最适宜pH为3.6,最佳催化温度为50℃。通过Michaelis Menten(米氏)方程计算得到的固定化酶的米式常数(Km)值较游离酶大,表明固定化酶的可重复使用性和储藏稳定性良好,连续使用10次后依然保留>50%酶活力,储藏1个月后固定化酶依然有81%的相对酶活力。 相似文献
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将羟乙基纤维素(HEC)与海藻酸钠(SA)进行混合,利用戊二醛交联处理后制备了HEC/SA高分子复合多孔薄膜,并探讨了其对模拟含铀废水中的六价铀(U(Ⅵ))的吸附特性。通过静态实验,探讨了初始pH值、U(Ⅵ)初始浓度、温度和吸附时间等对HEC/SA复合膜吸附U(Ⅵ)效果的影响;对吸附过程进行了热力学与动力学分析,利用FTIR、SEM和X射线能谱等手段分析了其吸附机制。实验结果表明,U(Ⅵ)的吸附量与温度正相关,吸附平衡时间约为90min,最佳吸附效果的初始pH值为5.0;吸附过程符合准二级动力学模型,主要表现为颗粒内部扩散;等温吸附过程符合Langmuir等温吸附线模型,在45℃时,HEC/SA复合膜对U(Ⅵ)的最大吸附容量达357.1mg·g-1,HEC/SA复合膜对U(Ⅵ)的吸附存在离子交换作用,与U(Ⅵ)的相互作用基团为羧基。 相似文献
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Poly(methyl methacrylate-ethyl acrylate-acrylic acid) latex particles with narrow size distribution and with surface carboxyl groups were produced by soap-free emulsion polymerization, and covalent immobilization of trypsin onto these particles was carried out by using the water-soluble carbodiimide (EDC) as an activating agent under various conditions. Different immobilization methods were employed and the factors affecting the efficiency and activity of the immobilized enzyme, such as the amount of trypsin and EDC, pH and temperature of the immobilization reaction were investigated. Results showed that both relatively high immobilization efficiency and high enzyme activity were achieved when pre-adsorption method was employed. The immobilization efficiency decreased as the trypsin amount increased, and increased as pH and temperature increased. When the EDC amount varied, the immobilization efficiency first increased significantly and then decreased slowly. A maximum of enzyme activity can be obtained at the optimum value of 958.0 mg trypsin/g dried particles and 372.5 mg EDC/g dried particles at 25 °C and pH 5.0. The immobilized trypsin exhibited much higher relative activity than its free counterpart. 相似文献
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Horseradish peroxidase was immobilized on the magnetic poly(glycidylmethacrylate-co-methylmethacrylate) (poly(GMA-MMA)), via covalent bonding and used for the treatment of phenolic wastewater in continuous systems. For this purposes, horseradish peroxidase (HRP) was covalently immobilized onto magnetic poly(GMA-MMA) beds using glutaraldehyde (GA) as a coupling agent. The maximum HRP immobilization capacity of the magnetic poly(GMA-MMA)-GA beads was 3.35 mg g(-1). The immobilized HRP retained 79% of the activity of the free HRP used for immobilization. The immobilized HRP was used for the removal of phenol and p-chlorophenol via polymerization of dissolved phenols in the presence of hydrogen peroxide (H(2)O(2)). The effect of pH and temperature on the phenol oxidation rate was investigated. The results were compared with the free HRP, which showed that the optimum pH value for the immobilized HRP is similar to that for the free HRP. The optimum pH value for free and immobilized HRP was observed at pH 7.0. The optimum temperature for phenols oxidation with immobilized HRP was between 25 and 35 degrees C and the immobilized HRP has more resistance to temperature inactivation than that of the free form. Finally, the immobilized HRP was operated in a magnetically stabilized fluidized bed reactor, and phenols were successfully removed in the enzyme reactor. 相似文献
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Baroni P Vieira RS Meneghetti E da Silva MG Beppu MM 《Journal of hazardous materials》2008,152(3):1155-1163
Removal of chromium ions from aqueous solutions by using natural and crosslinked chitosan membranes was achieved using batch adsorption experiments. The effect of pH (6.0 and 2.0), concentration of chromium ions and crosslinking agents (glutaraldehyde: GLA and epichlorohydrin: ECH) on the adsorption properties of chitosan membranes was analyzed. The experimental equilibrium data was fitted to Langmuir and Freundlich models. Through the model curves, it was possible to observe that the amount of chromium ions adsorbed was significantly higher for crosslinked membranes compared to non-crosslinked chitosan. The maximum adsorbed amount was about 1400 mg g(-1) for ECH-crosslinked chitosan at pH 6.0. The adsorption rates for crosslinked chitosan membranes with glutaraldehyde and epichlorohydrin were similar for natural chitosan. Desorption study using NaCl (1 mol L(-1)) solution was performed on chitosan membranes, in order to recover chromium ions and to determine the suitable number of cycles for repeated use of these membranes without considerable decrease in their adsorption capacity. The desorption results showed that chromium ions could be more effectively removed at pH 2.0 than pH 6.0, mainly for ECH-crosslinked chitosan. 相似文献
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Samantha Salomão Caramori Flaviana Naves de Faria Miriam Pereira Viana Kátia Flávia Fernandes Luiz Bezerra Carvalho 《Materials science & engineering. C, Materials for biological applications》2011,31(2):252-257
Discs of polyvinyl alcohol cross-linked with glutaraldehyde (PVAG) were synthesized and covered with polyaniline activated with glutaraldehyde (PANIG). Trypsin was covalently immobilized on this composite yielding a preparation containing 21.1 units per disc. The FT-IR spectra of the discs showed bands of PVA (3300 cm?1, 2930 cm?1 and 1440 cm?1) and PANI (1594 cm?1 and 1100 cm?1). The best immobilization conditions were: trypsin concentration at 0.2 mg mL?1, pH 7.6 and 60 min of incubation, similar to polyaniline–trypsin systems reported in the literature. The PVAG–PANIG–trypsin derivative showed an optimal pH and an optimal temperature of 7.0 and 35 °C, respectively. Hydrolysis of casein showed variations in the size of the products, revealing differences between the immobilized enzyme and the mechanism catalyzed by the native enzyme. 相似文献