稀酸预处理改善玉米秸秆酶水解性能的机制探讨

为了探讨在稀酸预处理提高玉米秸秆在纤维素酶酶解阶段提高纤维素转化率的机制,利用一系列的检测方法:FT-IR、XRD、SEM和比表面积分析仪分析了预处理前后玉米秸秆在形态学和物理化学性质方面的变化.在经过稀酸预处理后的玉米秸秆在纤维素酶酶解阶段其纤维素转化率有较大的提高,经过170℃,60 min,固液比1∶15(g∶mL),1.00 g/mL酸质量浓度的条件预处理后,从31.88％提高到95.74％.XRD结果显示预处理后玉米秸秆的结晶度有所增加,从原料的37.8％增加到58.7％,但是当预处理强度增加到一定程度后,结晶度没有较大的变化,基本维持在58％.玉米秸秆的表面结构在稀酸预处理后,原来的光滑表面变得粗糙、多孔,这样的表面有利于纤维素酶与玉米秸秆的接触,预处理后玉米秸秆的比表面积有很大程度的增加,经过170℃,60 min,固液比1∶15,1.00g/mL酸质量浓度的条件预处理后,玉米秸秆的比表面积从0.329 m2/g增加到2.878 m2/g,这都有利于改善纤维素酶对纤维素的作用,增加纤维素转化率.

Mechanism of Diluted Acid Pretreatment to Improve Enzymatic Hydrolysis of Corn Stover

In order to study the mechanism of diluted acid pretreatment on enhancing cellulose conversion during cellulase hydro-lysis process,microscopic structure and physical/chemical characteristics of corn stover before and after diluted acid pretreatment were investigated.The cellulose conversion ratio increased from 31.88 % to 95.74 % when the corn stover was pretreated by 1.875 % acid solution as a 1 ∶ 15 liquid ratio at 170 ℃ for 60 min.The XRD analysis showed that the crystallinity of cellulose increased from 31.88 % to 58.7 % after acid pretreatment.But only slight change of cellulose crystalline was observed when the corn stover was treated to some level.The rough fiber surface with more holes was detected after dilute acid pretreatment.This was beneficial for the connection between cellulose and corn stover.The specific surface area significantly increased from 0.329 m2/g to 2.878 m2/g after dilute acid pretreatment.It was also beneficial for enzymatic hydrolysis of corn stover cellulose.