龍鬚菜之酵素降解

Abstract

本研究探討以纖維素水解酶(Cellulase)水解醣類生質(蔗渣、龍鬚菜)的最佳條件(溫度50℃，pH 4.6)。並且比較醣類生質未經前處理及經過酸處理(基質加入0.2 M H2SO4，以殺菌釜加溫至121℃處理半小時)、冷凍前處理(基質加入去離子水浸泡，並於-10℃下靜置20分鐘)後的酵素水解速率差異。醣類生質經酵素水解成單醣、雙醣及寡醣後，再利用DNS (Dinitrosalicylic acid)定量還原端產生的量，以推估酵素水解效率。另外，利用酚-硫酸法以及葡萄糖感測器來定量酵素水解後產生的總醣濃度及葡萄糖濃度。本研究所開發的海藻生質，在經過冷凍前處理後確實提高了酵素水解速率以及醣類增加量，可望有效應用於生質能源領域。

Lignocellulosic biomass has been utilized to produce ethanol in the last two decades. The main process involved in this conversion is hydrolysis of cellulose in the lignocellulosic materials to produce reducing sugars. Due to the recalcitrant nature, the biomass can not be easily converted to monomeric sugars. Therefore, the low yield and high cost of the hydrolysis process are the major challenges in biomass energy development. In our research, marine seaweeds Gracilaria is used as the biomass. Owing to their hydration ability, an “Ice-crystal pretreatment” is developed to enhance the hydrolysis of cellulosic biomass. The enzymatic hydrolysate of biomass was measured by three methods. Reducing sugars is determined by the dinitrosalicylic method (DNS). Total soluble sugars is determined by the phenol-sulphuric acid method. Glucose is determined by the glucose biosensor. In our result, the validity of “Ice-crystal pretreatment” were confirmed. The effect of “Ice-crystal pretreatment” was also compared with acid pretreatment. In conclusion, marine seaweeds Gracilaria with “Ice-crystal pretreatment” may be a new approach to biomass energy development in the future.