微波辅助稀酸预处理玉米芯同步糖化发酵制备乙醇

Ethanol Production from Corncobs by Simultaneous Saccharification and Fermentation after Pretreatment with Dilute Acid Enhanced by Microwave

采用微波辅助稀酸预处理玉米芯以除去半纤维素和果胶等杂质,并降低纤维素的结晶度,然后经同步糖化发酵制备燃料乙醇,建立了制备乙醇的最佳工艺条件。利用热带假丝酵母种子液接种,发酵底物浓度20 g/100 m L,纤维素酶添加量质量分数为2%(相对于干物料),接种量体积分数为10%,150 r/min,33℃振荡培养48 h,终点乙醇产量达到30.98 g/L。采用分批补料方式,底物浓度提高到30 g/100 m L,其他条件不变培养60 h,终点乙醇产量达到41.23g/L。

Corncobs were pretreated with dilute H2SO4 solution enhanced by microwave to remove hemicellulose and reduce crystallinity of cellulose, and then subjected to simultaneous saccharification and fermentation （SSF）. The optimal fermentation conditions were obtained by the single factor test. Results showed that ethanol fermentation should be operated at the following conditions： Candida tropicalis Berkhout seed liquid was inoculated in the zymotic fluid, substrate concentration of 20 g/100 mL, cellulase dosage of mass fraction 2%, inoculation quantity of volume fraction 10%, 150 r/min, cultured for 48 h at 33℃. A final ethanol concentration of 30.98 g/L was achieved. A fed-batch process using a high substrate concentration was also studied. When the substrate concentration was increased to 30 g/100 mL, the highest ethanol concentration of 41.23 g/L was obtained after 60 h.