中山大学学报自然科学版 ›› 2011, Vol. 50 ›› Issue (6): 62-66.

• 研究论文 • 上一篇    下一篇

基于二级酶失活模型的纤维素酶反应动力学

张 宇,许敬亮,余 强,袁振宏,刘云云,亓 伟   

  1. (中国科学院广州能源研究所∥中国科学院可再生能源与天然气水合物重点试验室,广东 广州 510640)
  • 收稿日期:2011-06-22 修回日期:1900-01-01 出版日期:2011-11-25 发布日期:2011-11-25
  • 通讯作者: 袁振宏

Kinetics of Cellulase Based on the Model of Secondorder Enzymatic Deactivation

ZHANG Yu, XU Jingliang, YU Qiang, LIU Yun, YUAN Zhenhong,QI Wei

  

  1. (Key Laboratory of Renewable Energy and Gas Hydrate∥Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences, Guangzhou 510640, China)
  • Received:2011-06-22 Revised:1900-01-01 Online:2011-11-25 Published:2011-11-25

摘要: 酶催化、失活机制的模糊以及影响异相体系因素的大量存在,使得纤维素水解的酶催化过程高度复杂,很难为之建立机理模型。假定纤维素酶失活模型为二级反应,由准稳态理论推导出最终产物葡萄糖浓度与时间,初始酶浓度关系的半经验半理论模型。该模型只含两个参数,能对试验数据很好的拟合,相关系数R2均在0.98以上。用Bailey改进的米式方程进一步拟合不同初始酶浓度下的初速度关系,相关系数R2=0.9773,求得最大反应速度为2.7425 g/(L·h),半饱和常数为3.010 6 g/L。该模型还表明酶失活速率常数随着初始酶浓度的增加而减小,呈线性关系。失活速度随着初始酶浓度的增加而增加。

关键词: 准稳态理论, 纤维素酶失活, 异相催化, 数学模型, 动力学

Abstract:

Enzymatic hydrolysis of cellulose was extremely complex because of the unclear enzymatic hydrolysis, deactivation mechanisms and many factors that affect the heterogeneous system. Therefore, it is difficult to build a mechanistic model to study cellulose hydrolysis by cellulase. Under some assumed conditions such as the secondorder cellulase deactivation and quasi-steady state theory, a semi mechanistic and empirical model describing the relationship between product concentration and time, the initial enzyme concentration was deduced. The mathematic model was a simple mathematic function that contained only two parameters. The experimental result was in accordance with the deduced mathematic model, where the correlation coefficients (R2) were above 0.98. The relationship between initial enzyme concentration and initial hydrolysis rate calculated from the mathematic model showed good agreement with another type of Henri-Michaelis-Menten equation proposed by Bailey, where the R2 was 0.977 3. The maximum hydrolysis rate and half saturation constant was 2.742 4 g/(L·h) and 3.013 0 g/L, respectively. It was shown from the model that the rate constant of cellulase deactivation decreased when initial enzyme concentration increased under the certain substrate concentration, and the relationship between them was linear. The cellulase deactivation speed increased with the increase of enzyme concentration.

Key words: quasi-steadystate theory, cellulase deactivation, heterogeneous catalytic, mathematical model, kinetics

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