以多種前處理方式提升木屑葡萄糖糖化率之研究

生質酒精為綠色能源發展的重點，相較於以糧食作物作為生質物料的來源，近年來多以木質纖維素取代。由於木質纖維素結構緊密、不易分解，間接阻礙酵素對纖維素的水解以及醣類的發酵過程，利用有效的前處理方法可破壞木質纖維素之結構並解決以上問題。本研究以木屑作為生質酒精製程的木質纖維素來源，木屑為一種木質素含量極高的木質纖維素，木質素包覆著纖維素，使纖維素難以水解為葡萄糖，導致木屑極少用來進行纖維酒精的生產。本研究使用三種不同的前處理方法，分別為CO2爆破前處理、CO2加壓THF水溶液前處理、鹼性過氧化氫前處理，並將三種前處理方式互相搭配，其最佳方式為CO2加壓THF水溶液進行前處理，再以鹼性過氧化氫前處理，經此方式前處理之後，纖維素比例為72.0%、半纖維素比例為5.3%、木質素比例為19.8%，SEM圖顯示其木質纖維素結構已被高度破壞，由於半纖維素去除率為84.9%、木質素去除率79.3%，因此在酵素水解後，糖化率可達85.7%，高於純纖維素水解的糖化率76%。

關鍵字

木質纖維素；葡萄糖糖化率；鹼性過氧化氫；超臨界CO2爆破； CO2加壓THF水溶液

並列摘要

Bioethanol is the focus of green energy development. Instead of using food crops as a source of biomass, lignocellulose is an interested material recently. Because of the crystal structure of cellulose and cellulose covered by lignin, lignocellulose can’t get high sugar yield of the hydrolysis process and high bioethanol yield of fermentation process. The effective pretreatment method is needed to solve the above problems. In this study, wood dust was used as the source of lignocellulose in the bioethanol process. Wood dust is a kind of lignocellulose with extremely high lignin content. Lignin coats cellulose, making it difficult for cellulose to hydrolysis, resulting in very little use of woods for the production of bioethanol. This study uses a variety of different pretreatment methods, which are supercritical CO2 explosion pretreatment, CO2 compressed THF aqueous solution pretreatment, alkaline peroxide pretreatment, and combines these methods to make higher glucose recovery. The best way is CO2 compressed THF aqueous solution followed by alkaline peroxide pretreatment. After pretreating in this way, the proportion of cellulose is 72.0%, hemicellulose is 5.3%, and lignin is 19.8 %. The SEM image also shows that its lignocellulose structure has been highly destroyed. 84.9% of hemicellulose is removed, and delignification is 79.3%. Therefore, after enzyme hydrolysis, the glucose recovery could reach 85.7%, which is higher than that 76% of pure cellulose hydrolysis.