不同条件对纤维素糖化反应动力学参数的影响

Effect of the Kinetics of Cellulose Saccharification under Different Conditions

DOI：10.3969/j.issn.1673-1689.2019.09.006

中文关键词: 纤维素 水解 糖得率 动力学

英文关键词: cellulose,hydrolysis,sugar yield,kinetics

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中文摘要:

纤维素是秸秆中发酵生产生物燃料的主要成分，将纤维素转化为可发酵性糖是秸秆发酵合成生物燃料的关键步骤。以糖得率作为指标，研究了不同反应条件对纤维素糖化反应的动力学模型参数的影响。The Impeded Michaelis Model（IMM）能很好的拟合试验数据，模型包含酶与底物的可接近度（K_obs，0）和酶活性逐渐损失率（K_i）等两个参数。当pH 4.41，温度47 ℃，纤维素酶质量浓度3 g/dL，底物质量浓度5 g/dL时，可获得糖得率Ytrs为46%，K_obs，0为0.265 4 h-1，K_i为0.058 3 h-1，与实验结果基本一致。温度和pH主要通过改变无效酶系数影响糖得率，而酶质量浓度和底物质量浓度主要改变酶对底物的可接性作用于糖得率；在试验浓度范围内Ytrs和K_obs，0呈正相关关系，和K_i成负相关关系，对木质纤维素的糖化研究奠定了基础。

英文摘要:

The cellulose is the main component of the strain to produce bio-fuel. The saccharification of cellulose to fermentable sugars is critical step to fermentation of stalk to synthesize biofuel. The effects of various reaction conditions on parameters of the kinetics of cellulose saccharifications reaction were studied using the sugar yield（Ytrs） as an index. The Impeded Michaelis model containing two parameters including the accessibility between enzyme and the substrate（K_obs，0） and the gradual loss of enzyme activity（K_i） could be fitted all experimental data well. The predicted maximum Ytrs（46%），K_obs，0（0.265 4 h-1），Ki（0.058 3 h-1）was obtained under the following conditions：pH of 4.41，temperature of 47 ℃，3% cellulase and 5% corn stover based on the model. The predicted results was in line with the experimental results. Temperature and pH mainly increase Ytrs by decreasing Ki，and the enzyme solubility and substrate concentration increases Ytrs mainly by increasing K_obs，0. Ytrs is significantly positively correlated with K_obs，0and negatively correlated with K_i. This study lays the foundation for the saccharification of lignocellulose.

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