低浓度乙酸预处理玉米芯的工艺研究

Pretreatment of Corncob by Dilute Acetic Acid

以脱除木质素,降解半纤维素为木糖,提高纤维素酶解得率为目的,研究了低浓度乙酸预处理玉米芯的效果,考察了乙酸质量分数、预处理温度和时间对预处理的影响。研究结果表明:质量分数5%乙酸预处理玉米芯可以脱除大部分的半纤维素和少部分木质素,预处理后的玉米芯具有较好的水解效果。低浓度乙酸预处理玉米芯最优条件为:预处理温度160℃,保温时间60 min,乙酸质量分数5%,固液比1∶8(g∶mL)。在此条件下,玉米芯固体渣回收率为53.75%,固体渣中纤维素保留率93.17%,半纤维素脱除率87.36%,木质素脱除率25.04%,预处理液中木糖质量浓度15.56 g/L。预处理后的玉米芯固体经72 h酶解,酶解得率为92.69%。

A dilute acetic acid pretreatment technology for corncob was established to remove lignin,convert hemicellulose into xylose and improve the enzymatic hydrolysis yield.The effects of acetic acid concentration,pretreatment temperature and time on pretreatment goal were investigated and the results showed that most of the hemicellulose and partial lignin in the corncob were removed by pretreating with 5%acetic acid.Moreover,the pretreated corncob was easy to be hydrolyzed.Under the optimal condition(pretreatment temperature of 160℃,holding time of 60 min,acetic acid concentration of 5%and solid-liquid ratio of 1∶8(g∶mL),the yield of corncob solid residue was 53.75%,the cellulose retention rate of corncob solid residue could reach 93.17%,and 87.36%of the hemicelluloses and 25.04%of the lignin were removed.Meanwhile,15.56 g/L xylose was obtained from the pretreatment liquid.The maximum enzymatic hydrolysis yield of pretreated corncob solid could be up to 92.69%within 72 h.