改良優養化藻類醣化效率提升生質乙醇產量技術之研究

優養化問題已威脅到國人用水的安全，若前端污染源控制成效不彰，則需仰賴後端高效率的處理技術，然而，所產生的廢棄物亦有二次污染的風險，倘若能整合現有技術，收集水體中藻類，並轉製成生質乙醇，不但可解決優養化問題，更使得能源永續發展及達到前瞻發展願景。過去研究證實電混凝/浮除法是高效率的藻類收集技術，犧牲電極產生的鐵金屬雖有助於增加醣化反應速率及還原糖的產率，但累積於藻體間的金屬氫氧化物，造成單位藻重的碳水化合物含量降低及醣化後生成物對乙醇發酵產生抑制作用等問題。另外優養化水體存在大量雜質，使稀酸醣化過程受到干擾，而增加酸用量，因此，為解決上述問題，本研究採用電浮除(石墨)技術收集優養化水體藻類，以減少金屬離子衍生的問題，並增加洗滌前處理技術，降低雜質的干擾。研究結果顯示，比較未經前處理技術及經前處理技術的組別，其總還原醣產率分別為0.242 g reducing sugar/g algae與0.288g reducing sugar/g algae，最終透過酵母菌Pichia stipitis (BCRC 21775)於最佳發酵條件下，最高乙醇濃度分別為2.28 g/L與2.86 g/L，最高乙醇產率分別為0.082 g ethanol/g algae與0.101 g ethanol/g algae。

關鍵字

優養化；電浮除(石墨) ；洗滌前處理；醣化；生質乙醇； Pichia stipitis

並列摘要

The eutrophication has threatened the safety of drinking water. If the front-end pollution control is not effectiveness, it needs to rely on the highly efficient back-end process technology that generates the waste with risk of secondary pollution. It collects algae in the water if existing technologies are integrated into new process, and converted into bioethanol. Not only can solve the eutrophication, but also make sustainable energy development and achieve forward looking development vision. In the past, the electro-coagulation/flotation was established to be a highly efficient algal collection technology. The ferrous metal from sacrificial electrode contributes to the increase saccharification reaction rate and the reducing sugar yield but metal hydroxide accumulates in algae. As result of the reduction of carbohydrate content and inhibition of fermentation. In addition, eutrophication of water body contains a large amount of impurities that interferes with dilute acid saccharification process. As result of increasing usage amount of acid. In order to solve the above problems, this study use electro-flotation(graphite) technology to collect eutrophic algae for avoiding a metal ion derived problems and add the washing pretreatment to reduce the interference of impurities. This result shows that the total reducing sugar yield of pretreated and unpretreated group were respectively 0.242 g reducing sugar/g algae and 0.288 g reducing sugar/g algae. Under optimum ferment conditions by Pichia stipitis (BCRC 21775),the highest ethanol concentration is 2.28 g/L and 2.86 g/L , the highest ethanol yield is 0.082 g ethanol/g algae and 0.101 g ethanol/g algae.