以前處理提升稻殻纖維素水解效率之研究

Abstract

本研究以稻殼為原料，探討利氫氧化鈉與硫酸，於不同溫度（30、60、90℃），不同濃度（0.25、0.2、0.15M）與不同前處理時間（20、40、60分鐘）等條件下進行前處理，先分析前處理後之水解液含還原糖之濃度，再利用纖維酵素水解脢，於pH值4.6、溫度50℃、酵素液濃度21U/mL、基質比1%等條件下就殘留之固體進行酵素水解；並探討前處理溫度、時間與酸濃度對於酵素水解轉換率之影響。研究結果發現：在前處理溫度90℃下，酸水解液中之還原醣濃度隨著酸濃度與前處理時間之增加而增加，鹼處理液則不然。經過0.25M之氫氧化鈉，於前處理溫度90℃、前處理時間60分鐘條件下前處理者，其後續之酵素水解效果最好，其總轉換率可達到80%。 關鍵字：乙醇、酸處理、鹼處理、稻殼、酵素水解。

Rice hull, a complex lignocellulosic material with high lignin and ash content, has the potential to serve as a low-cost feedstock for production of ethanol. In this study, rice hull was pretreated by dilute NaOH and H2SO4 at different temperature (30, 60, 90°C) with different concentration(0.25, 0.2, 0.15 M) and different treatment time（20、40、60 minutes）. Reducing sugars in the hydrolyzate are analyzed. The solid residues were hydrolyzed by cellulase from Trichoderma reesei C2730 under conditions of pH(4.6), temperature (50℃), enzyme concentration (21U/mL) and enzyme to substrate ratio (1%). The effects of pretreatment time, temperature and acid/base concentration on enzymatic hydrolysis are studied. The effect of acid pretreatment is not obvious. Results show that alkaline pretreatment can enhance the saccharification. Pretreated rice hull hydrolyzed with Trichoderma reesei C2730 cellulase showed 80% sacchrification. Keywords: ethanol; acid pretreatment; alkaline pretreatment; rice hull; enzymatic hydrolysis