膨化预处理玉米秸秆的还原糖酶解工艺

Enzymatic hydrolysis of reducing sugar in expansion pretreated corn straw

应用膨化技术对玉米秸秆进行预处理。在单因素实验基础上,以还原糖转化率为影响值设计正交实验,研究温度、pH、液固比、酶浓度及酶解时间五因素对纤维素酶解过程的影响。得出玉米秸秆糖化酶解最佳工艺条件为:温度48℃,pH 4.5,液固比8∶1,酶浓度36.0 U/g,酶解时间25 h;在此工艺条件下还原糖转化率达到28.98%。扫描电镜表征对比观察可看出,膨化后玉米秸秆纤维素酶解充分;结合红外光谱对各组分特征基团分析表明,膨化后的玉米秸秆酶解的纤维素基团特征峰变化更为明显。

The corn straw was pretreated by expansion technology. Orthogonal experiment was designed by choosing conversion rate of reducing sugar as influence value basing on the single factor experiment. The influ- ences of temperature, pH, liquid-solid ratio, enzyme concentration and time on the cellulose enzyme solution process were studied. Results showed that the optimum conditions were as follows： enzymolysis temperature of 48℃ , pH of 4.5, liquid-solid ratio of 8： 1, enzyme concentration of 36.0 U/g, enzymolysis time of 25 h. The conversion rate of reducing sugar is 28.98% under the conditions. The enzymolysis of cellulose of corn straw is complete after expansion pretreatment by scanning electron microscopy （SEM）. The characteristic peak of cellu- lose in enzymolysis process changes obviously after expansion pretreatment by infrared spectrum.