响应曲面法优化小麦秸秆纤维素酶水解条件

Optimization of Enzymatic Hydrolysis of Wheat Straw by Using Response Surface Methodology

利用响应曲面试验设计方法(RSM),选择底物质量分数、酶投加量、温度、p H值及水解时间为试验因子,还原糖(RS)产率为响应值,考察小麦秸秆纤维素酶水解过程中各影响因子对还原糖产率的影响,对小麦秸秆纤维素酶水解条件进行优化。结果表明,所考察的5个影响因子对还原糖产率均具有显著影响(p<0.05)。所得回归方程R2值为0.946 9,p<0.05,变异系数(CV)值为4.37%,足够精度值为26.396,说明模型高度显著,可以在设计范围内对响应值进行预测。模型预测最佳水解条件为底物质量分数8.0%,酶投加量为35 FPU/g(以秸杆质量计),温度50℃,p H值5.4,水解时间96 h。利用最优水解条件进行验证试验,所得还原糖产率为60.73%,水解液中葡萄糖和木糖质量浓度分别为31.84和16.74 g/L。

With an aim to optimize the conditions of enzymatic hydrolysis of wheat straw,the parameters including solid content, enzyme loading,temperature,pH,and hydrolysis time were investigated by means of response surface methodology（ RSM） with the reducing sugar（RS） yield as response value. The results showed that all the parameters had significant effects（p＆lt;0. 05） on the reducing sugar yield. A well fitted regression equation with R2 value of 0. 946 9,p＆lt;0. 05,coefficient variability（Cv） value of 4. 37%,and adequate precision value of 26. 396 indicated that the developed model was significant and could be used to navigate the designed space and predict the response. The predicted optimum conditions for enzymatic hydrolysis were solid content of 8. 0%,enzyme loading of 35 FPU/g, temperature of 50 ℃, pH of 5. 4, and hydrolysis time of 96 h. The experimental results showed that under the optimum conditions the corresponding RS yield was 60. 73% with glucose and xylose concentrations of 31. 84 and 16. 74 g/L,respectively. Further,the results obtained in this research showed a high RS yield with high initial solid content,which would significantly improve the ethanol concentration,reduce the subsequently distillation costs,and improve the commercial potential of the lignocellulosic bioethanol production.