共查询到18条相似文献,搜索用时 78 毫秒
1.
2.
3.
微球载体固定化纤维素酶的反应动力学模型研究 总被引:1,自引:0,他引:1
建立了固定化纤维素酶的反应动力学模型,该模型以米氏方程为基础并考虑了产物竞争性抑制的影响。在此模型的基础上进行模拟,系统研究了产物竞争性抑制、内扩散限制、溶液中的宏观底物浓度、载体大小等因素对球形载体内部的底物、产物浓度分布和效率因子的影响。产物竞争性抑制的存在将增加载体颗粒内的底物浓度,对效率因子的影响较小。底物内扩散系数或者反应体系中底物浓度增大时,载体颗粒内的底物浓度和效率因子都将增大。载体粒径增大,载体颗粒内的底物浓度和效率因子均减小。 相似文献
4.
5.
纤维素酶液体发酵最佳培养基的确定 总被引:11,自引:0,他引:11
用响应面法对里氏木霉WX—112液体发酵产纤维素酶的培养基进行了优化。首先用快速登高路径逼近最大产酶区域,然后根据快速登高法的实验结果进行响应面实验。运用逐步回归分析法,获得滤纸酶活与豆饼粉、麸皮、KH2PO4、微晶纤维素粉(Avicel)的最优回归方程,且分析了各因子间的交互效应。最后,通过岭脊分析确定了滤纸酶活达最大值10.53IU/mL时的最佳组合条件:豆饼粉3.18%、麸皮2.95%、KH2PO4 0.25%、Avicel 3.79%。 相似文献
6.
秸秆质外体蛋白对纤维素酶活力的影响 总被引:4,自引:0,他引:4
研究了玉米秸秆在储存过程中质外体蛋白含量的变化情况,及其对Penicilllumexpansum纤维素酶活力的影响。结果表明随着储存时间的延长,可抽提的玉米秸秆质外体蛋白的数量逐渐减少,与P.expansum纤维素酶的协同作用也随之减弱。储存玉米秸秆质外体蛋白没有内源性纤维素酶活力,而新鲜玉米秸秆有内源性EG活性,但它的稳定性较差,储存半年后基本降解或失活。储存秸秆质外体蛋白对FPA酶活力、棉花酶活力、β-葡萄糖苷酶活力有明显的增效作用,最大增效分别达到95.32%、102.06%和96.6%。而对CMCase却表现出抑制作用,最大抑制率为49.52%,质外体蛋白-EG-βG表现出明显的协同关系,而它对CBH酶活力没有影响。消除内源性EG的影响后,新鲜玉米秸质外体蛋白对FPA活力、棉花酶活力、β-葡萄糖苷酶活力的促进率,以及CMCase的抑制率均高于储存秸秆的质外体蛋白。可见质外体蛋白是天然纤维素酶解研究不可忽视的影响因素。 相似文献
7.
8.
9.
10.
影响纤维素酶水解木屑的若干因子的研究 总被引:4,自引:0,他引:4
木霉201,79、SA3和1096产生的纤维素酶对天然木屑的水解能力都极其低微,但当木屑氮过适当的预处理以后,酶的永解能力明显地提高。X2-85菌纤维素酶在45℃保温24h,酶活损失15%左右。用三种底物考察酶用量与酶解率之间的关系:酶浓度增加100%,木纸浆的酶解增长率为120%,脱脂棉的酶解增长率为31%,酸处理木粉的酶解增长率为2%。差别很悬殊,说明提高酶解率的主要途径,是把对酶亲和力小的木屑转变为对酶亲和力大的底物。 相似文献
11.
Yukihiko Hayashi Moto Kitayaki Kayoko Takezaki Hidekazu Ikeuchi Shigeru Kunugi 《Biocatalysis and Biotransformation》2013,31(1):25-31
The contribution of three exoglucanases from a commercial Trichoderma viride cellulase to transcellobiosylation, and the tolerance of these enzymes to acetonitrile co-solvent were studied. The enzymatic reactions were performed with p-nitrophenyl-β-d-cellobioside as the starting substrate. Among these enzymes, the least anionic exoglucanase (Exo I) showed the highest transcellobiosylation activity and acetonitrile tolerance. Exo I retained considerable activity even in 30% MeCN/water and produced p-nitrophenyl-β-d-cellotetraoside at about 1.5% conversion from the initial substrate in 30% MeCN/water. The residual activity of Exo I after incubation in MeCN/water mixture was almost identical to that of the crude cellulase and a considerable amount of the transcellobiosylation properties of the crude cellulase seemed to be attributable to this Exo I component. 相似文献
12.
Yukihiko Hayashi Moto Kitayaki Kayoko Takezaki Hidekazu Ikeuchi Shigeru Kunugi 《Biocatalysis and Biotransformation》2003,21(1):25-31
The contribution of three exoglucanases from a commercial Trichoderma viride cellulase to transcellobiosylation, and the tolerance of these enzymes to acetonitrile co-solvent were studied. The enzymatic reactions were performed with p-nitrophenyl-β-d-cellobioside as the starting substrate. Among these enzymes, the least anionic exoglucanase (Exo I) showed the highest transcellobiosylation activity and acetonitrile tolerance. Exo I retained considerable activity even in 30% MeCN/water and produced p-nitrophenyl-β-d-cellotetraoside at about 1.5% conversion from the initial substrate in 30% MeCN/water. The residual activity of Exo I after incubation in MeCN/water mixture was almost identical to that of the crude cellulase and a considerable amount of the transcellobiosylation properties of the crude cellulase seemed to be attributable to this Exo I component. 相似文献
13.
Marli Camassola Luciano Ramos De Bittencourt Nicole T. Shenem Jürgen Andreaus 《Biocatalysis and Biotransformation》2013,31(5-6):391-396
New cellulases from a strain of Penicillium echinulatum were characterized for their filter paper activity and β-glucosidase activity. Both activities showed maximum values between pH 4 and 5. With citrate buffer, activities were slightly higher than in acetate buffer of the same pH. Thermal stability of both activities was good up to 55°C. Filter paper activity was significantly reduced at higher temperatures. 相似文献
14.
O.I. Shadyro I.P. Edimecheva G.K. Glushonok N.I. Ostrovskaya G.I. Polozov H. Murase 《Free radical research》2013,47(10):1087-1097
Investigation of effects produced by 26 various phenol and diphenol derivatives, including industrial and natural antioxidants (ionol, bis-phenol 2246, α-tocopherol), on final product yields of radiation-induced free-radical processes involving peroxyl, alkyl, α-hydroxyalkyl and α,β-dihydroxyalkyl radicals has been performed. Ionol and bis-phenol 2246 have been shown to be more effective than α-tocopherol or diphenol derivatives in suppressing hydrocarbon oxidation processes. At the same time, α-tocopherol and its water-soluble analogues, as well as diphenol-based substances, are more effective than phenol derivatives in regulating various homolytic processes involving carbon-centered radicals. This fact can be accounted for by taking into consideration the contribution to formation of the final product set and the respective yields made by semiquinone radicals and compounds with quinoid structure arising in the course of homolytic transformations in systems containing diphenol derivatives. 相似文献
15.
Marli Camassola Luciano Ramos De Bittencourt Nicole T. Shenem Jü rgen Andreaus Aldo Jos Pinheiro Dillon 《Biocatalysis and Biotransformation》2004,22(5):391-396
New cellulases from a strain of Penicillium echinulatum were characterized for their filter paper activity and β-glucosidase activity. Both activities showed maximum values between pH 4 and 5. With citrate buffer, activities were slightly higher than in acetate buffer of the same pH. Thermal stability of both activities was good up to 55°C. Filter paper activity was significantly reduced at higher temperatures. 相似文献
16.
高活力纤维素酶菌株康氏木霉B—7的选育与产酶条件的研究 总被引:14,自引:0,他引:14
野生型康氏木霉854-B_2分别经物理化学诱变因子,TDP辐射器和空间微重力辐射等因素的多级处理,得到1株形态发生明显改变的变异株B—7,其固体培养物的纤维素酶各组分酶活力,如滤纸糖酶活力(FPA)为34u/g,羧甲基纤维素酶活力(CMC—ase)为29.0u/g,β-葡萄糖苷酶活力(β-Glase)为29.0u/g,与854-β2相比,分别提高5.9倍,7.6倍和4.2倍。其固体培养的最佳条件是:pH6.0,28~30℃,96小时,最适培养基成分为:青草粉:麸皮=7:3,1.5~2.0倍水和(NH4)2SO41.5~2.0%(均以固体料计)。 相似文献
17.
复合菌系WSD-5具有高效的分解能力和产酶能力,以探明WSD-5的协同分解机理和优化高效组合为目的,通过纯培养分离手段,获得了11株细菌和3株真菌。16S rDNA比对结果表明,细菌分别为Pseudomonas sp.、Pseudomonas aeruginosa、Achromobacter sp.、Stenotrophomonas sp.、Bacillus fusiformis、Bacillus cereus、Brevundimonas sp.、Ochrobactrum sp.、Cytophaga sp.、Benzo(a)pyrene-degrading bacter、Flavobacterium sp.的近缘种;26S rDNA比对结果表明3株真菌分别为Pseudallescheria boydii、Coprinus cinereus的近缘种。分离菌株中有4株细菌和3株真菌能在CMC平板上产生透明圈,但以糖化力法测定酶活结果只有3株真菌具有产酶能力。3株真菌的酶活动态测定结果,酶活的高峰均出现在7?14 d,并且呈现多峰变化;3株真菌的酶活种类表现为,滤纸酶活性、纤维素内切酶活性和外切酶活性均以菌株F1最高,分别达到了1.05、5.53和0.56 U/mL,β-葡萄糖甘酶活性和木聚糖酶活性以菌株FC最高,分别达到0.44和58.95 U/mL,其木聚糖酶活为F1最高值的6倍。 相似文献
18.
李堆淑 《基因组学与应用生物学》2019,38(3):1123-1130
以灰色链霉菌为原料,在单因素试验的基础上,采用响应面法试验,优化灰色链霉菌产纤维素酶活性的发酵条件。结果表明,单因素试验灰色链霉菌产纤维素酶活性的最适发酵条件:碳源为CMC-Na,氮源为明胶,温度为28℃,pH为7.0,转速为130 r/min。响应面法试验优化灰色链霉菌产纤维素酶活性最佳发酵条件为:温度27.7℃,pH值6.9,转数130.3 r/min,在此优化条件下,灰色链霉菌产纤维素平均酶活性为6.103 U/mL(n=3),与模型的预测值(6.217 U/mL)比较接近,误差为1.83%,证明了该响应面模型具有可靠性。 相似文献