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聚丙烯酸甲酯载体对柱状假丝酵母脂肪酶固定化的研究(Ⅰ) 总被引:4,自引:1,他引:4
合成了一系列不同结构的聚丙烯酸甲酯,考察了它们的固定化酵母脂肪酶催化酯水解反应的效果,得到了载体孔结构对固定化效果影响的一些规律.研究了最佳吸附条件,比较pH和离子强度对酵母脂肪酶自由酶和固定化酶催化酯水解反应活力的影响. 相似文献
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用悬浮聚合法合成了一系列聚甲基丙烯酸羟乙酯载体,考察了它们固定化酵母脂肪酶活力与载体的交联度和致孔剂用量之间的关系。研究了这些固定化酵母脂肪酶在有机溶剂中催化酯合成反应的活性,脂肪酶的固定化使之活力表达更为充分,对亲水性较强的有机溶剂有更强的耐受性,并能为其在有机溶剂中催化酯合成反应提供必需水。考察了PH值,底物种类对固定化酵母脂肪酶催化酯合成反应的影响。 相似文献
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猪胰脂肪酶的固定化及其在有机相中催化丁酸甲酯和正丁醇的酯交换反应研究 总被引:1,自引:0,他引:1
考察了大孔苯乙烯-二乙烯苯交联共聚物的交联度、致孔剂量及胺化试剂对载体固定化猪胰脂肪酶的影响。选择出一种最佳载体对猪胰脂肪酶进行固定化,对比了自由酶和固定化酶在有机相中催化丁酸甲酯和正丁醇的酯交换反应。结果表明,酶经固定化后催化反应活力比自由酶提高近1倍。 相似文献
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猪胰脂肪酶的固定化及其在有机相中催化丁酸甲酯和正丁… 总被引:2,自引:2,他引:2
考察了大孔苯乙烯-二乙烯苯交联共聚物的交联度、致孔剂理及胺化试剂对载体固定化猪胰脂肪酶的影响。选择出一种最佳载体对猪胰脂肪酶进行固定化,对比了自由酶和固定化酶在有机相中催化丁酸甲酯和正丁醇的酯交换反应。结果表明,酶经固定化后催化反应活力比自由酶提高近1倍。 相似文献
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采用界面活化的溶胶凝胶包埋Candida rugosa脂肪酶(CRL)催化合成了维生素E琥珀酸酯.考察了影响溶胶凝胶包埋固定化CRL的因素,获得的最佳固定化条件为:丙基三甲氧基硅烷/正硅酸四乙酯摩尔比为1/1,水与硅烷前体摩尔比为15,酶的添加量为0.5mg/ml,PEG400的添加量为12μl/ml溶胶. 溶胶凝胶包埋的CRL在50℃,18h后其活性仍然保持了70.58%,是游离酶的2.6倍,且稳定性得到了明显的改善.基于CRL的界面特性,采用五种表面活性剂对其进行界面活化.结果表明,采用橄榄油活化的溶胶凝胶包埋的CRL合成维生素E琥珀酸酯的酯化活力最高,相比原酶和未界面活化的溶胶凝胶包埋酶分别提高了6.7和1.43倍. 相似文献
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利用X射线微区分析的方法,对吸附交联法得到的固定化脂肪酶的微观活性进行了分析。结果表明:以合成出的大孔吸附树脂为固定化酶栽体,酶活较高,活性脂肪酶分布较均匀。并得到了固定化脂肪酶的活性定位的最佳条件。 相似文献
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降解萘的黄杆菌ND3菌株的固定化研究 总被引:2,自引:0,他引:2
用海藻酸盐做载体,用包埋法将降解萘的黄杆菌ND3菌株固定化,对固定化菌的制备条件及固定化菌降解萘的条件作了筛选,在适宜条件下,固定化黄杆菌连续培养48h后,对萘的降解率可达98%以上。 相似文献
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Pinheiro RC Soares CM de Castro HF Moraes FF Zanin GM 《Applied biochemistry and biotechnology》2008,146(1-3):203-214
The conditions for maximization of the enzymatic activity of lipase entrapped in sol–gel matrix were determined for different
vegetable oils using an experimental design. The effects of pH, temperature, and biocatalyst loading on lipase activity were
verified using a central composite experimental design leading to a set of 13 assays and the surface response analysis. For
canola oil and entrapped lipase, statistical analyses showed significant effects for pH and temperature and also the interactions
between pH and temperature and temperature and biocatalyst loading. For the olive oil and entrapped lipase, it was verified
that the pH was the only variable statistically significant. This study demonstrated that response surface analysis is a methodology
appropriate for the maximization of the percentage of hydrolysis, as a function of pH, temperature, and lipase loading. 相似文献
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Brányik Tomáš Kuncová Gabriela Páca Jan Demnerová Kateřina 《Journal of Sol-Gel Science and Technology》1998,13(1-3):283-287
This work deals with changes in microbial phenol degradation and cell proliferation caused by immobilization into silica gel. Mixed microbial culture and the yeast Candida tropicalis were immobilized in silica layers and pieces prepared by mixing of prepolymerized tetraethoxysilane with cell suspension. The phenol degradation rate of cells entrapped in silica gel was compared with those immobilized into an organic polymer-polyurethane. The phenol degradation efficiency decreased in the following order: free cell suspension > cells entrapped into polyurethane foam > cells entrapped into prepolymerized TEOS. Inside the silica there was no growth observed by optical microscope. The immobilization of bacterium Pseudomonas species 2 into silica gel, cells which co-metabolize PCBs with biphenyl, did not result in substantial change of intermediate concentration. 相似文献
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Immobilization of whole-cell penicillin g acylase by entrapping within polymethacrylamide beads 总被引:2,自引:0,他引:2
Liang-Tzung Hsiau Wen-Chien Lee Feng-Sheng Wang 《Applied biochemistry and biotechnology》1997,62(2-3):303-315
Escherichia coli ATCC 11105 containing the periplasmic penicillin G acylase was entrapped within a copolymer of methacrylamide andN,N’- methylenebisacrylamide. A solution of monomer that was made up from methacrylamide andN,N’-methylenebisacrylamide dissolved in buffer was mixed with lyophilized cells and ammonium persulfate. This suspension was
then pumped drop by drop into in soybean oil supplemented with 0.06% (v/v) 3-(dimethylamino)-propionitril. During submerging
in the oil phase, the droplets were hardened and induced to polymerize within the droplets. Particles with a volume ranging
from 0.013–0.017 mL per bead containing a biomass concentration up to 38.0 g/L were prepared. The optimal condition for the
deacylation of penicillin G to 6-aminopencillanic acid (6-APA) catalyzed by the immobilized whole-cell penicillin G acylase
was found to be 45‡C and pH 8.0. Product inhibition of this enzyme by 6-APA could be eliminated by controlling pH value at
8 during the course of penicillin G hydrolysis using a pH-stat. Conversion determined by the pH-stat method were 0.3% higher
than that by p-dimethylaminobenzaldehyde method. Cell concentration in the matrix was found to be an important factor influencing
the maximum velocity and the specific activity retained in the matrix. A kinetic model, in which the mass transfer resistances
as a result of external film mass transfer and pore diffusion were assumed to be negligible, could properly describe the hydrolysis
of penicillin G by the cells entrapped within the polymethacylamide beads. 相似文献
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分别在对二氧环己酮均聚物和对二氧环己酮-乙交酯共聚物中加入增塑剂进行纺丝,制得聚对二氧环己酮单丝缝合线(PDS)和对二氧环己酮-乙交酯共聚物单丝缝合线(PDG).用DSC方法研究了增塑剂含量对PDS缝合线热性能的影响和不同热定型条件的PDG缝合线的热性能,测试了热定型温度对PDG缝合线初始强度、模量及柔量的影响,考察了增塑剂含量对两种缝合线的生物降解性能和力学降解性能影响.研究结果表明,PDS缝合线的玻璃化转变温度Tg、结晶温度Tc以及熔融温度Tm均随着增塑剂含量的增加而降低,但其结晶能力增加.随着热定型温度的增加,PDG缝合线的初始打结强度、熔融热均提高,熔融温度Tm基本保持不变.两种缝合线的强度保留率随着增塑剂含量的增加均先增加后减小,而重量保留率随着增塑剂含量增加始终减小. 相似文献
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C. Dosoretz R. Armon J. Starosvetzky N. Rothschild 《Journal of Sol-Gel Science and Technology》1996,7(1-2):7-11
The present work reports on the entrapment of parathion hydrolase from Pseudomonas spp. into the sol-gel glass matrix. Enzyme entrapment was studied in the range of 0.01–0.25 U, and compared with the activity of the free, non-immobilized enzyme. The reaction catalyzed by the entrapped enzyme was almost two orders of magnitude slower than with the free enzyme. Addition of surfactants slightly increased the parathion hydrolysis rate, and the addition of ethanol almost doubled it. However, this increase of reaction rate cannot by itself explain the decrease of activity, suggesting that irreversible damage to the enzyme during gelation, rather than diffusion limitation throughout the gel-glass structure, is the main cause for the decrease of activity. Regardless of damage to the enzyme during gelation, the remaining entrapped active fraction displayed stability even after eleven days, during successive cycles of the same entrapped enzyme batch, each for 24 h. The sol-gel entrapped enzyme retained relatively good activity for several months when stored as a dry powder, and over a year when kept in buffer solution, at ambient conditions. The results obtained may give a rise to the use of entrapped parathion hydrolase for simple on-field bio-detection of organophosphates. 相似文献
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J. G. Kaplan 《Photochemistry and photobiology》1963,2(3):333-338
Abstract— Suspensioris of aerobic and anaerobic yeast were subjected to ultraviolet radiation (principally 254 mµ ) under closely comparable experimental conditions, and changes in the level and in the temperature dependence of their catalase activity were determined. Qualita tively, the effects of U.V. on the enzyme of the anaerobic cells were similar to those on that of the aerobic cells. The effect of U.V. on the anaerobic catalase differed from that on the aerobic enzyme in the following respects: I, a considerably greater dose of U.V. was necessary in order to attain the maximum activity and the minimum activation energy of the enzyme-substrate system; 2, a far greater dose was required before appreciable photoinactivation of the maxi mally active enzyme occurred; 3, photoinactivation proceeded at less than one-half the rate; 4, the u.v.-induced increase in the catalase activity of the suspension was virtually complete before appreciable reduction in activation energy occured. The first three of these differences were interpreted in terms of a model, which pictures the anaerohic catalase as being tightly bound to an intracellular chromophore group. 相似文献
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