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疏水吸附性载体上附加基团对天冬氨酸酶性质的影响 总被引:1,自引:0,他引:1
6-氨基已酸和四乙烯基五胺通过高碘酸氧化法分别引入到邻甲苯胺基琼脂珠(TA)衍生物上,得到CTA和ATA,天冬氨酸酶在pH5.5,0.1mol/L磷酸缓冲液中,0.5mol/L KCl存在下通过疏水吸附固定化在TA,CTA和ATA上。结果表明三种固定化酶活力回收均达90%以上,同TA-天冬氨酸酶相比,CTA-酶,ATA-酶的最适pH,pH稳定性等均有所改变,其中ATA-酶的热稳定性,使用稳定性增强 相似文献
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接枝淀粉载体固定化糖化酶的研究 总被引:1,自引:0,他引:1
合成了淀粉接枝丙烯腈及丙烯酰胺的两亲性高分子化合物,并以此为载体,用物理吸附方法固定化了糖化酶。最适偶联条件研究表明:缓冲液的浓度,pH值及吸附时间和加酶量都对固定化酶活力,比活有一定的影响。在最适固定化条件下,固定化酶的活力为1500U/g干胶,蛋白载量为25mg/g干胶,比活为60U/mg蛋白,比天然酶的比活(8.0U/mg蛋白)提高6倍。最适反应温度比天然酶提高10℃(天然酶最适反应温度为50℃).无底物存在下,固定化酶在55℃的半衰期为24h,而天然酶只有1h;有底物存在下,固定化酶在55℃的半衰期为220h,45℃的操作半衰期由外推法算得为69天,而且该载体对糖化酶有一定的保护作用,当固定化酶在低于55℃热处理一段时间后,对酶活力有激活作用,酶活力最大可提高40%。该载体合成简单,固定化方法简单,步骤少,因而为工业上应用提供了一种新的可能性。 相似文献
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具有磁响应性的聚乙二醇载体固定化糖化酶的研究 总被引:7,自引:0,他引:7
以两亲性的聚乙二醇胶体粒子,通过吸附-交联法固定化糖化酶。研究了戊二醛浓度,缓冲液pH值及加酶量对酶固定化的影响,固定化酶活力可达17095Upergram干胶,活力回收为63%。磁性固定化酶最适温度比天然酶提高5℃,最适pH比天然酶提高05个pH单位。并且对酸、碱、热的稳定性大大增强,贮存及操作稳定性也大大提高。该磁性载体合成简单,固定化方法简便,具有磁性,易于分离,因而为工业上的应用提供了一种新的可能。 相似文献
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为研究tRNA^Trp与色氨酰-tRNA合成酶(TrpRS)的相互识别及其结构、功能关系,纯化了枯草杆菌TrpRS并用溴化氰活化的Sepharose4B将TrpRS固定化,固定化TrpRS的蛋白质回收率为为95.5%,活力回收率为31.3%。研究了固定化TrpRS的酶学性质。其热稳定性和贮存稳定性方面均比液相TrpRS有了较大的提高,最适温度、最适pH均有一定程度的增大,工作稳定性良好。以固定化T 相似文献
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本文研究了用吸附交联技术共固定化蔗糖酶和葡萄糖氧化酶(GOD)的方法,考查了共固定化酶的动力学性质。试验结果表明:与溶液酶相比较,固定化蔗糖酶和GOD的响应滞迟期分别为3分钟和2分钟,4态响应时间增加6分钟和4分钟,Km值增大,pH─活力曲线变宽,最适pH值分别增大0.7和0.64,最适温度则降低7.3℃和16℃。以活性氧化铝作载体,戊二醛作交联剂制备的共固定化蔗糖酶和GOD,其蛋白质固定化率为92.9%,分解葡萄糖的总速度为441.6IU,当蔗糖浓度在0.2%以内时其反应速度与蔗糖浓度呈正相关(r=0.996),使用半衰期1623次,在4℃下保存120天活力残存为83.7%。 相似文献
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无花果蛋白酶通过8%戊二醛活化载体,共价结合到聚苯乙烯阴离子交换树脂GM201上,固定化作用在pH7.7,酶浓度0.8mg/g树脂,4℃下进行6h。得到的固定化酶表观K_m值(酪蛋白,1.11×10~(-4)mol/L)小于溶液酶K_m值(1.96×10~(-4)mol/L);固定化酶活性在pH6~8保持稳定,溶液酶最适pH为7.2;固定化酶最适温度由溶液酶的50~60℃移至37℃;固定化酶25℃保持7d,重复水解酪蛋白7次后,保留83.3%活性。固定化酶对酪蛋白水解度达47.5%,对大豆球蛋白达11.6%。 相似文献
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以卡拉胶为载体,固定化棒状杆菌(Corynebacterium sp.)JZ1菌株细胞,再经活化处理,顺式环氧琥珀酸水解酶(ESH)酶活力总回收率在100%以上。摇瓶反应10批,酶活力没有明显降低。1500L酶柱中连续运行90d,酶稳定性很好。固定化后酶反应的最适温度(45℃)和最适pH(90)没有改变,而热稳定性、pH稳定性增强 相似文献
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Nocardia tartaricans converted sodium cis-epoxysuccinate to L-tartrate. The highest cis-epoxysuccinate hydrolase activity (37.7 U mg–1) was obtained with 0.02% (w/v) sodium deoxycholate, but this inactivated the cells. Immobilized N. tartaricans in pectate gel showed higher enzyme activity (51 U mg –1) compare to the free cells (8.9 U mg –1). After 450 days, the immobilized cells still possessed 0.65 U mg –1, i.e. 30% of the initial enzyme activity. 相似文献
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顺式环氧琥珀酸水解酶产生菌的筛选及产酶条件 总被引:4,自引:1,他引:4
从65株诺卡氏菌中,筛选到一株产顺式环氧琥珀酸水解酶(ESH)的菌株,经鉴定为酒石酸诺卡氏菌(Nocardia tartaricans)SW13-57。在14L发酵罐中通过诱导培养,能在细胞内产生ESH酶活力达120u/g。产酶条件研究表明用丙二醇作碳源,硫酸铵作氮源,顺式环氧琥珀酸作诱导剂,初始pH7.0,温度30℃,通过培养24~30h,产酶量最高。该产酶菌株已被用于固定化细胞方法连续生产L(+)酒石酸。 相似文献
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顺式环氧琥珀酸水解酶(CESH)是根瘤菌BK-20生产L(+)-酒石酸的关键酶。为提高其生产效率和生产稳定性,首先优化根瘤菌BK-20的产酶条件,然后利用固定化细胞连续生产L(+)-酒石酸。结果显示,优化后游离细胞酶活达(3 498.0±142.6)U/g,较优化前提高643%。固定化细胞酶活达(2 817.2±226.7)U/g,其最适包埋剂、菌体浓度和凝胶浓度分别为海藻酸钠,10%(W/V)和1.5%(W/V)。固定化细胞连续反应10批后,其形状和酶活均无明显改变,单批次转化率达98%以上,具有良好的生产稳定性。 相似文献
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Whole cells of Escherichia coli having high aspartase (L-asparate ammonialyase, EC 4.3.1.1) activity were immobilized by entrapping into a kappa-carrageenan gel. The obtained immobilized cells were treated with glutaraldehyde or with glutaraldehyde and hexamethylenediamine. The enzymic properties of three immobilized cell preparations were investigated, and compared with those of the soluble aspartate. The optimum pH of the aspartase reaction was 9.0 for the three immobilized cell preparations and 9.5 for the soluble enzyme. The optimum temperature for three immobilized cell preparations was 5--10 degrees C higher than that for the soluble enzyme. The apparent Km values of immobilized cell preparations were about five times higher than that of the soluble enzyme. The heat stability of intact cells was increased by immobilization. The operational stability of the immobilized cell columns was higher at pH 8.5 than at optimum pH of the aspartase reaction. From the column effluents, L-aspartic acid was obtained in a good yield. 相似文献
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Five different chemical reagents and γ‐rays were tested for the sanitization of immobilized biocatalysts with high penicillin G acylase (PGA) activity. The most effective chemical reagents were N‐cetyl‐N,N,N‐trimethylammonium bromide (CTAB) and 2‐isopropyl‐5‐methylphenol (thymol). The optimum concentration of CTAB for the treatment of the immobilized enzyme was 0.25% [w/v] and 1 h, for immobilized cells 0. [w/v] and 3 h. The optimum concentration of thymol for the immobilized enzyme was found to be 0.1% [w/v] and 1 h, for immobilized cells 0.27% [w/v] and 2 h. The optimum dose of γ‐rays for the sanitization of the immobilized enzyme was established as 3.2 kGy, for immobilized cells as 4.5 kGy. 相似文献
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本文研究了用海藻酸钙包埋法制备含谷氨酸脱羧酶固定化细胞的方法以及研究了制备的条件和影响其制备的因素。该法具有包埋细胞活力回收高,方法简便等优点。比较研究了固定化细胞和自然细胞谷氨酸脱羧酶的一些生物化学性质。其中固定化细胞最适pH和pH稳定性增加,最适温度及热稳定性下降;表观米氏常数增大;二价金属离子Zn~(++)、Cu~(++)、Mg~(++)、Fe~(++),Sr~(++)程度不同的抑制酶活性,Ca~(++)激活固定化细胞酶活性,EDTA无抑制作用。对固定化细胞和自然细胞酶活力活化的研究中发现这两种细胞经蒸馏水保温处理后酶活性都上升,且自然细胞酶活的上升较固定化细胞大;而用底物溶液处理后,自然细胞无变化,固定化细胞酶活下降。 相似文献
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Kluyveromyces marxianus cells with inulinase (2,1-β-d-fructan fructanohydrolase, EC 3.2.1.7) activity have been immobilized in open pore gelatin pellets with retention of > 90% of the original activity. The open pore gelatin pellets with entrapped yeast cells were obtained by selective leaching out of calcium alginate from the composite matrix, followed by crosslinking with glutaraldehyde. Enzymatic properties of the gelatin-entrapped cells were studied and compared with those of the free cells. The immobilization procedure did not alter the optimum pH of the enzymatic preparation; the optimum for both free and immobilized cells was pH 6.0. The optimum temperature of inulin hydrolysis was 10°C higher for immobilized cells. Activation energies for the reaction with the free and immobilized cells were calculated to be 6.35 and 2.26 kcal mol?1, respectively. Km values were 8 mM inulin for the free cells and 9.52 mM for the immobilized cells. The thermal stability of the enzyme was improved by immobilization. Free and immobilized cells showed fairly stable activities between pH 4 and 7, but free cell inulinase was more labile at pH values below 4 and above 7 compared to the immobilized form. There was no loss of enzyme activity of the immobilized cells on storage at 4°C for 30 days. Over the same period at room temperature only 6% of the original activity was lost. 相似文献
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梨头霉菌在有机相中的最适固定化条件及其反应特性的研究 总被引:3,自引:0,他引:3
采用海藻酸钙凝胶固定化淡紫色梨头霉菌并在有机相中转化11-脱氧皮质醇醋酸酯(RSA)为皮质醇,研究了最佳固定化和转化条件。实验结果表明,固定化菌体的最佳培养周期为18小时。固定化菌体可被重复使用6次,而转化活性没有明显降低。 相似文献
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[目的]产顺式环氧琥珀酸水解酶(CESH)新型菌株的筛选、鉴定及其产酶条件优化.[方法]通过电镜、Biolog GN、(G C)含量和16S rDNA序列研究,对筛选菌株进行分类鉴定.通过红外光谱、核磁共振氢谱和碳谱、质谱以及旋光度实验,鉴定纯化产物的结构并优化CESH产酶条件.[结果]本文筛选出一株产CESH的新型菌株,该菌株可将顺式琥珀酸盐转化为D(-)-酒石酸,属于博德特氏菌属,并将其命名为博德特氏菌BK-52.最佳发酵条件为:最佳温度30℃,最佳pH7.0,最佳发酵时间36 h,最佳碳源蔗糖,最佳无机氮源硫酸铵,最佳酶诱导剂顺式环氧琥珀酸二钠.在此最佳条件下,CESH酶活最高达764 U/g生物量.[结论]本文筛选的新菌株博德特氏菌BK-52为D(一)一酒石酸的生产提供了一种新的方法. 相似文献
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Isao Karube Shinichi Kuriyama Tadashi Matsunaga Shuichi Suzuki 《Biotechnology and bioengineering》1980,22(4):847-857
A methanogenic population was immobilized onto agar gel, polyacrylamide gel, and collagen membrane. Agar-gel-entrapped methanogenic microorganisms gave the highest activity. The optimum agar concentration was between 1.5 and 3% (w/v), and the optimum microbial content was 20 mg wet cells/g gel. The optimum conditions for methane production by immobilized whole cells were pH 7.0–7.5 and 37–45°C. The rate of methane production was initially 1.8 μmol/g gel/hr. Methane productivity was gradually increased and reached a steady state (4.5μmol/g gel/hr) after 25 days of incubation. The immobilized methanogenic microbial population continuously evolved methane over a 90 day period. No difference in methane productivity was observed after three months of storage at 5°C. Methane was also produced by immobilized whole cells under aerobic conditions. Furthermore, carbohydrates, such as glucose, in wastewater completely decomposed by immobilized whole cells. 相似文献