稀酸预处理玉米芯酶解工艺响应面优化研究

木质纤维原料还原糖（葡萄糖、木糖）转化是燃料乙醇生产的关键步骤之一，该文以玉米芯为原料，采用稀硫酸处理、酶水解以提高还原糖转化量。以还原糖转化量为考核指标，采用单因素试验及响应面试验设计优化稀酸处理玉米芯酶解条件，拟合硫酸体积分数、加酶量、酶解时间3个因素对还原糖转化量的回归模型。结果表明，最佳酶解工艺为121 ℃条件下预处理60 min，硫酸体积分数0.8%，料液比1∶15（g∶mL），加酶量7%（纤维素酶∶半纤维素酶1∶1），酶解时间70.9 h。在此最佳条件下，采用高效液相色谱（HPLC）法测定酶解液中还原糖转化量为462.62 mg/g，其中木糖、葡萄糖转化量分别为330.02 mg/g、132.60 mg/g，还原糖转化率可达46.3%。

Optimization of enzymolysis process of corncobs with dilute acid pretreatment by response surface methodology

The conversion of lignocellulosic biomass to reducing sugar (glucose and xylose) was one of key processes in the fuel ethanol production. To increase the concentration of glucose and xylose, corncobs was pretreated with dilute acid firstly and hydrolyzed with cellulase and hemicellulase. The enzymatic hydrolysis conditions of corncob were optimized by single factor and response surface experiments using reducing sugar conversion amount as evaluation index, and the regression model according to the significances and interaction effects of acid concentration, enzyme addition and hydrolysis time on the sugar conversion amount was fitted. The results indicated that the optimum conditions was determined as follows: sulfuric acid concentration 0.8%, solid-liquid ratio 1:15 (g:ml), 121 ℃ for 60 min, enzyme addition 7.0% (cellulose: hemicellulase 1:1) for 70.9 h. Under the condition, the reducing sugar conversion amount determined by HPLC reached 462.62 mg/g and conversion rate was up to 46.3%, including xylose 330.02 mg/g and glucose 132.60 mg/g.