纤维素酶预处理漂白针叶木浆的工艺优化研究

Study on the Optimization of Cellulase Pretreatment of Bleached Softwood Pulp

机械法制备纳米纤维素前增加酶预处理工艺,不仅可以大幅度降低机械能耗,而且制备出的产品尺寸分布更均匀。采用纤维素酶预处理结合机械法对漂白针叶木纤维原料进行处理,利用单因素实验法和响应面实验法,研究酶预处理对PFI磨后纤维形态和形貌等性能影响的一般规律,探讨条件因素间的交互作用对响应值的影响显著性,根据各因素对响应值影响显著性进行排序,并给出优化结果。单因素实验结果表明,酶解时间90 min、酶解温度55℃、酶用量150 mg/kg、酶解环境pH值8.5,为最佳酶预处理条件。应用响应面法建立模型并对工艺参数进行优化的结果表明,酶解时间90 min、酶解温度48℃、酶用量150 mg/kg、酶解环境pH值7.5,为优化结果;模型预测纤维平均长度为1.835 mm,验证实验纤维平均长度为1.817 mm;酶用量与酶解时间、酶用量与酶解温度、酶解时间与酶解温度交互作用对响应值影响显著;条件因素对响应值影响显著性排序为:酶用量>酶解时间≈酶解温度>酶解环境pH值。

Enzyme pretreatment process can not only greatly reduce mechanical energy consumption,but also receive uniformly distributed products in mechanical preparation of nanocellulose process.Cellulase pretreatment combined with mechanical method was used to treat bleached softwood fiber.Single factor test method and response surface methodology were used to study on the effect of cellulase pretreatment on the fiber’s morphology after PFI grinding and the significance of the interaction between conditional factors on the response value was explored to sort each factor by the influence significance on the response value and obtain the optimization results.Results of single factor method showed that the optimal enzymatic pretreatment conditions were enzymatic hydrolysis time of 90 min,enzymatic hydrolysis temperature of 55℃,the enzyme dosage of 150 mg/kg,and the enzymatic hydrolysis pH value of 8.5.The response surface methodology was used to establish the model and optimize the process parameters.The results showed that the optimal enzymatic pretreatment conditions were enzymatic hydrolysis time of 90 min,enzymatic hydrolysis temperature of 48℃,the enzyme dosage of 150 mg/kg,and the enzymatic hydrolysis p H value of 7.5.The average fiber length predicted by the model was 1.835 mm and the average fiber length verified by the test was 1.817 mm.The interaction between enzyme dosage and enzymatic hydrolysis time,enzyme dosage and enzymatic hydrolysis temperature,enzymatic hydrolysis time and enzymatic hydrolysis temperature had a significant effect on the response value.The order of significance of the influence of conditional factors on the response value was:enzyme dosage>enzymatic hydrolysis time≈enzymatic hydrolysis temperature>enzymatic hydrolysis environment pH value.