利用不同前處理提高纖維酵素水解酸菜尾效率之研究

Abstract

新興工業國家對於石油需求增加，造成全球石油資源日漸缺乏，目前石油整體需求高於供給，油價高居不下，意味高能源價格時代來臨。酸菜醃漬後所遺留之大量殘餘物（醃漬液、酸菜尾），由於具有高含量的鹽份，不易處理，若不積極改善，將嚴重危害周遭環境，日積月累導致農地日漸鹽化。因此本研究針對酸菜醃漬產生之剩餘物料，研究其再利用之方法；所以本實驗針對酸菜尾進行生產纖維酒精前處理之研究與評估，讓酸菜殘餘物能夠適宜的處理後，期望未來能使酸菜產業於兼顧環保之餘得以永續經營。本研究於不同前置處理下（熱水前置處理、冷水前置處理、未經前置處理），比較前置處理對於組成分析方法之探討，找出較佳的前置處理後使用不同前處理（蒸汽爆裂前處理、高壓加熱配合不同濃度之酸鹼前處理、熱水靜置配合不同濃度之酸鹼前處理）後，然後配合酵素水解製程後研究其最佳的酸菜尾轉化酒精製程。 結果中原料組成分析需使用熱水前置處理，使酸菜尾中高量的雜質及萃取物降低，以達到較為精確的組成分析結果。前處理最佳的葡萄糖轉化率條件為高壓加熱配合使用2M H2SO4酸前處理下作用，轉化率為22％；而木糖轉化率條件最佳者則為高壓加熱配合使用0.37M H2SO4作用下，轉化率達45％，和蒸汽爆裂前處理相比，蒸汽爆裂前處理之葡萄糖轉化率近15％，木糖轉化率30％，結果均未高於高壓加熱酸前處理之效果。酵素水解製程中最佳之葡萄糖轉化率為使用高壓加熱配合0.37M H2SO4酸前處理組，酵素水解轉化率達50％，木糖轉化率則普遍較低。使用高壓加熱酸前處理組的0.37M H2SO4實驗組有最佳之葡萄糖和木糖總轉化率（葡萄糖總轉化率為55％，木糖總轉化率達45％）。使用最佳之前處理製程配合酵素水解製程後，若將所得之固渣及水解液進一步進行發酵，整體理想總酒精生產率為218 mg/g dry weight （分別為164 mg/g glucose 和 54 mg/g xylose）。

Because of the climate change, geopolitical and other factors, global oil resources reduced gradually. Nowadays the overall oil demand is higher than the supply, especially in emerging industrial countries, the lack of oil resources caused the high oil price, which means the era of high energy prices is coming. After the fermentation process, pickled mustard left the large amount of residues (pickling liquor, pickled mustard waste). Because of the high salt content, it’s not easy to deal with the waste. If we do not actively deal with this problem, it will harm the surrounding environment seriously. Pickled mustard waste from Dapi township contained large amounts of salt, it probably leads to the increase of salinization of agricultural land for a long time. Therefore, my study aimed at the methods of the textural change and re-use of residue fiber to develop the ethanol production and related program. Pickled cabbage residues are treated appropriately to keep on pickled cabbage industry under environmental protection and sustainable development. Under the pretreatment of high heat and high pressure with 2 M H2SO4, the best glucose conversion is 22%; the best xylose conversion is 45% under the high heat and high pressure combined with 0.37 M H2SO4. Compared to steam explosion pretreatment, the glucose and xylose conversion are 15% and 30%, respectively. The results showed that the conversions are not higher than the formers. In the enzymatic hydrolysis process, the pretreatment of the best glucose conversion is high pressure and high heat pretreatment with 0.37 M H2SO4, the glucose conversion is 50%, but xylose conversion is generally low. Under high heat and high pressure with 0.37M H2SO4, the pretreatment has the best conversion of glucose and xylose (total glucose conversion is 55%, total xylose conversion is 45%). It was deduced that the process of effective pretreatment can break down the lignocellulosic structure of biomass. The cleaning procedure after pre-treatment will not lead to acid/base solution left in the solid residue, and therefore the conversion efficiency of enzymatic hydrolysis is better. Using the best pretreatment condition with the hydrolysis process, the solid residue and the hydrolyzed liquid collected after treatment continue the fermentation process, the ideal total alcohol production is 218 mg/g dry weight (164 mg/g glucose and 54 mg/g xylose, respectively).

Keywords: pickled mustard, biomass ethanol, the pretreatment process, the conversion of glucose and xylose.