近年來由於能源危機和石油價格高漲，以農業廢棄物做為基質生產生質酒精為研究議題漸受重視，也有許多文獻及研究成果，足以說明生質能源目前占有的地位。 本研究透過固態發酵培養Aspergillus niger，大量生產纖維水解酵素，並於醣化步驟中提出有別於傳統的醣化方法。傳統的醣化方法為添加純化的纖維水解酵素，近來亦有自行生產酵素的操作，但仍會經過粗製的純化或是分離菌體的步驟。在本研究中提出控制環境參數以省略上述步驟，抑制菌體生長及使還原糖累積，達到節省成本之效果。在醣化步驟中發現纖維水解酵素為醣化的主要因素，進而提出延長酵素活性之方法。最後用醣化後發酵液利用Saccharomyces cerevisiae進行酒精發酵。 由實驗結果顯示，固態發酵能生產較高單位的纖維水解酵素，利用黃豆及稻稈培養最高可得到23.85 U/gdm，單位基質對酵素活性轉化率最高可到12.88 U/gds。第二階段醣化步驟中可藉由提升溫度使酵素活性增高並抑制Aspergillus niger生長；及藉由厭氧在第三階段中抑制Aspergillus niger利用還原糖。在醣化步驟中加入20g/L經鹼處理過的稻稈可得到最高11.58 g/L的還原糖，轉化效率為58.42 ％。實驗亦說明酵素活性是影響還原糖累積的主要因素。透過添加PMSF或持續添加自行生產的酵素可延長酵素活性。而應用於酒精發酵，可得最大酒精濃度2.00 g/L，轉化效率為86.71 ％。 The strain used in this study was Aspergillus niger which could product lots of cellulase by solid state fermentation. Traditional saccharification method used commercial purified cellulase. In the recent year, there were some operating which producing celluase from microorganisms, but it still need to extract crudely or separate the microorganism. A novel method in saccharification step is proposed to easily operate in this study. By controlling environmental parameters like temperature or oxygen to inhibit the growth of Aspergillus niger, the culture resulted in the accumulation of reducing sugar. The operation not only remove the complex steps but also achieve the target of cost down. Cellulase activity is the main controlling factor in the saccharification step, thus we proposed to extend the method of cellulase activity. Finally, ethanol was obtained by Saccharomyces cerevisiae after saccharification fermentation broth. The experimental results show that solid-state fermentation can produce higher unit cellulase activity, and the highest cellulase activity obtained as 23.85 U/gdm by soybean and rice straw. Saccharification step could be utilized to enhance the enzyme activity and to inhibit the growth of Aspergillus niger by increasing temperature. Anaerobic operating can inhibit Aspergillus niger as a result that the reducing sugar was produced at the second step. In the saccharification step, adding 20 g/L of alkali-treated rice straw can obtain the highest 11.58 g / L of reducing sugar, the conversion efficiency was 58.42%. Adding PMSF as a protease inhibitor or adding more cellulase was can extend the cellulase activity. Applied to the fermentation of ethanol, the maximum ethanol concentration can be obtained as 2.00 g / L and the conversion efficiency as 86.71%.
