共查询到19条相似文献,搜索用时 234 毫秒
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漆酶固定化及其性质研究 总被引:7,自引:0,他引:7
本文就漆酶的固定化及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固定化漆酶.结果表明:固定化酶米氏常数Km为12.0mg/ml,游离酶米氏常数Km为7.0mg/ml,固定化酶最适温度为40℃,游离酶为30℃.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。 相似文献
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壳聚糖微球固定化葡萄糖氧化酶的研究 总被引:17,自引:1,他引:17
以壳聚糖微球为载体,戊二醛为交联剂,固定葡萄糖氧化酶,对葡萄糖氧化酶的固定化条件及固定化酶的各种性质进行了研究,确定了酶固定的最佳条件为0.1g壳聚糖微球与5ml5%戊二醛交联,固定6mg葡萄糖氧化酶,在此条件下酶活力回收可达60%。固定化酶的最适温度为50℃,最适pH为6.0,通过Lineweaver-Burk作图,确定动力学参数Km值为18.3mmol/L,表观米氏常数较游离酶有所降低,固定化酶的热稳定性较游离酶明显提高,该固定化酶具有良好的操作及保存稳定性。 相似文献
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针对现有材料对漆酶的负载率低,负载漆酶后重复使用性能差等缺点,以甲基丙烯酸羟乙酯(HEMA)为单体,采用原子转移自由基聚合(ATRP)技术对工业化生产的水刺粘胶纤维膜进行改性处理,然后将改性后的水刺粘胶纤维膜 (即SV-poly(HEMA))进行Fe3+吸附,最后将吸附Fe3+后的SV-poly(HEMA)(即SV-poly(HEMA)- Fe(Ⅲ))作为配位法固定漆酶的载体,探究其对漆酶固定化的含量、活性、稳定性和重复使用性能,同时对纤维形貌和结构进行表征。结果表明:SV-poly(HEMA)-Fe(Ⅲ)对漆酶的固定化量达到132.9 mg/g;与自由漆酶相比,固定化漆酶对温度变化(20~70 ℃)表现出更强的抵抗力,对pH值(2.0~7.0)表现出更低的敏感性;将负载漆酶的SV-poly(HEMA)-Fe(Ⅲ)重复使用10次后,漆酶的活性依然保持在55%以上。 相似文献
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新型交联剂三羟甲基磷固定化脂肪酶的研究 总被引:1,自引:1,他引:0
本试验研究了一种新型交联剂三羟甲基磷(THP)用于以纯棉浴巾载体、聚乙烯亚胺(PEI)为吸附剂的固定化脂肪酶制备新方法。通过单因子实验获得了固定化条件为:0.2 g浴巾使用0.5 mLPEI(浓度3.37 mg/mL,pH 7.0)、2 mLTHP(浓度为0.10%,V/V)、固定化温度为40℃、交联时间为20 min。制备的固定化脂肪酶催化正丁酸乙烯酯与戊醇酯交换反应,1 h底物转化率达92.1%,酶比活力达到15.80 U/g固定化酶。与戊二醛(GA)交联法制备的固定化酶相比,本固定化酶具有良好的重复使用稳定性、温度稳定性和高比活力,本试验采用的方法是一种低成本、实用性强的脂肪酶固定化新方法。 相似文献
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Koroleva OV Stepanova EV Gavrilova VP Yakovleva NS Landesman EO Yavmetdinov IS Yaropolov AI 《Journal of Bioscience and Bioengineering》2002,93(5):449-455
The white-rot fungus Coriolus hirsutus strain 075 excretes considerable amounts of laccase and Mn-peroxidase into culture broth over a brief production time. The effects of agitation speed, temperature, aeration and inoculum amount on laccase production using a 10-l fermentor were studied. The optimum fermentation conditions were a 15% inoculum, an aeration rate of 0.88 vvm, an agitation speed of 160 rpm, and a temperature of 28 degrees C. By optimizing the fermentation conditions, the laccase activity reached 80+/-3 U/ml in 3 d and the purified enzyme output was 30 mg/l. The laccase and Mn-peroxidase were purified by means of isoelectrofocusing and ion-exchange chromatography. The pIs of the laccase isoenzymes were 4.2 and 4.5. Mn-peroxidase had only one isoenzyme with a pI of 3.2. The optimum pH was 4.5 for laccase with syringaldazine as the substrate and 5.0-5.3 for Mn-peroxidase with Mn(+2) and H2O2 as the substrates. The laccase and Mn-peroxidase retained 50% of their activities at 50 degrees C after 55 h and 12 h of incubation time, respectively. 相似文献
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Michaela Dina Stanescu Simona Gavrilas Roland Ludwig Dietmar Haltrich Vladimir I. Lozinsky 《European Food Research and Technology》2012,234(4):655-662
A new biocatalyst was prepared by the immobilization of a Trametes pubescens laccase, into a wide-pore poly(vinyl alcohol) cryogel. The known enzyme was produced and purified by the previously described
procedure. The resulted laccase (yield 40%) has an activity of 46.4 U mg−1 and 12.51 mg mL−1 protein content. The enzyme was subsequently immobilized in a functionalized macroporous cryogel beads by a covalent immobilization
technique. The time dependence of the immobilization process and the enzyme loading of the carrier material (5.2 mg g−1 cryogel) were determined by measuring the decrease of protein amount in the enzyme solution. In conversion experiments, a
higher stability of the immobilized biocatalyst compared to the free enzyme was evidenced. Steady-state kinetic characterization
of four phenols (catechol, caffeic and chlorogenic acids, and catechin) has been performed with free and immobilized laccase,
the catalytic parameters being determined and compared. The effect of both laccases (free and immobilized) on the phenol content
of retailed apple juice samples, having the same initial composition, was also investigated by working in batch conversion.
The variation in phenolic compound content has been compared with that of an untreated apple juice sample having initially
the same content of phenolic compounds. A number of advantages resulted in using the immobilized laccase for the apple juice
treatment (conservation to some extent of enzyme activity, higher content of phenols preserved, easy separation of the enzyme
from the apple juice, therefore avoiding the possible unhealthy effects due to the remaining protein, etc.). 相似文献