Effects of ultrasonic intensity and reactor scale on kinetics of enzymatic saccharification of various waste papers in continuously irradiated stirred tanks
Effects of ultrasonic intensity and reactor scale on kinetics of enzymatic saccharification of various waste papers in continuously irradiated stirred tanks
复制标题
DOI：
10.1016/j.ultsonch.2004.02.004
复制
发表时间：
2005-04-01
影响因子：
8.4
通讯作者：
Nakao, K
中科院分区：
文献类型：
--
作者：
Li, CZ;Yoshimoto, M;Nakao, K
在之前0.8升超声搅拌釜反应器中对各种纸浆进行酶解糖化的基础上，在同一反应器以及3.2和6.4升的更大规模搅拌釜反应器中对报纸、纸箱纸、办公用纸等废纸进行超声强化糖化。在一定的超声波强度下，在较大的反应器中，每种废纸的糖化作用增强较小。这可归因于单位反应体积的超声强度的降低，即，超声波的具体强度。大多数废纸更有效地水解与增加特定的超声波强度，虽然报纸是不太有效地做了一个太高的特定强度。这种不利影响可能是由于报纸中的一些杂质如木质素被强烈的超声波辐射活化，形成刚性和封闭的网络，这抑制了纤维素酶在基材表面的接近和吸附。上述动力学模型适用于分析和模拟各种废纸在不同超声波反应器中的糖化过程。基于无限反应时间估计的总糖浓度的底物的最终转化率可以作为在固定的特定超声强度下初始底物与酶浓度的比率的函数而相关。除报纸外，表观速率常数和最终转化率均随超声比强度的增大而增大并趋于一常数，而表观米氏常数、产物抑制常数和葡萄糖生成平衡常数均不受超声比强度的影响. (C)2004 Elsevier B.V.保留所有权利。
Based on the enzymatic saccharification of the various pulps in the previous 0.8 l ultrasonic stirred tank reactor, the ultrasound-enhanced saccharification of waste papers such as newspaper, carton paper, office paper etc. was carried out in the same reactor as well as larger scale stirred tank reactors of size 3.2 and 6.4 l. The saccharification of each waste paper was less enhanced in the larger reactor at a given ultrasonic intensity. This could be attributed to the decrease in the ultrasonic intensity per reaction volume, i.e., the specific ultrasonic intensity. Most waste papers were more efficiently hydrolyzed with increasing specific ultrasonic intensities, although newspaper was less efficiently done for a too high specific intensity. Such an adverse effect might be due to the fact that some impurities in the newspaper such as lignin were activated by an intensive ultrasonic irradiation to form a rigid and closed network, which inhibited the access and adsorption of cellulase on to the substrate surface. The previous kinetic model was found to be applicable to analyze and simulate the saccharification of each waste paper in the different ultrasonic reactors. The ultimate conversion of a substrate based on the total sugar concentration estimated for an infinite reaction time could be correlated as a function of the ratio of initial substrate to enzyme concentrations at a fixed specific ultrasonic intensity. Either the apparent rate constant or the ultimate conversion increased and tended to approach a constant with an increase in the specific ultrasonic intensity except for the case of newspaper, while neither the apparent Michaelis constant, product inhibition constant nor glucose formation equilibrium constant was influenced by the specific ultrasonic intensity. (C) 2004 Elsevier B.V. All rights reserved.