探討稻桿經由不同前處理供Bacillus sp.培養之研究

Effects of various pretreatment of rice straw on the cellulase production by Bacillus sp.

葉宇軒(YU-HSUAN YEH)

指導教授 ： 徐敬衡

國立中央大學/工學院/化學工程與材料工程學系/碩士(2012年)

摘要

許多農業廢棄物蘊藏了豐富的木質纖維素是被眾多學者們視為重要資源來作為能源的使用，而農業廢棄物稻桿組成中包含將近40%之纖維素，經過前處理能有效去除木質素含量來增加纖維素所占比例，並且使得微生物分解纖維素的效率提升。
本研究主要討論稻桿在經過不同前處理後，作為Bacillus sp.發酵之基質可行性，分別採用鹼處理、離子液體處理及結合上述兩種方式的結合式處理，其中以離子液體選用、毒性測試、重複回收使用之糖化率作為研究重點。
由實驗結果顯示，稻桿經由鹼處理後，纖維素組成由原先37.4%上升至56.6%，經兩種結合式處理上升至65.6%及63.2%；而當 [AMIM]Cl 存在於培養基之濃度超過0.5%時，會對菌體生長造成抑制，[BMIM]Cl濃度在1%內對菌體生長則未有明顯改變；稻桿經酵素水解72小時後糖化率之比較發現結合式處理為85.3%及75.4%，效果明顯優於鹼處理35.1%與未處理時之7.86%；結合式處理經重複使用五次時之糖化率依然能維持初次使用使之83%及93.4%；未經處理稻桿作為發酵基質時之Yp/s為0.044，經結合式處理上升至0.178及0.198。

關鍵字

離子液體 ； 前處理 ； 木質纖維素

並列摘要

Lignocellulosic biomass and crop wastes have been considered as potential sustainable feedstocks for energy production. Rice straw is an abundant and attractive lignocellulosic byproduct which contains nearly 40% cellulose. Different pretreatment methods can be used to enhance the digestibility of cellulosic materials.
In this research, we investigated three kinds of pretreatments including alkali-treatment, ionic liquids (ILs)-treatment and combined method. We focused on the choice of ILs, toxicity test and ILs reuse as the research key point.
According to this study, rice straw treated by alkali-treatment can increase cellulose component from 37.4% to 56.6%, treated by two combined methods can increase cellulose component to 65.6% and 63.2%. We discovered when ionic liquid [AMIM]Cl exist over 0.5% in medium would inhibit bacillus sp. growth and ionic liquid [BMIM]Cl compared to [AMIM]Cl , it has lower toxicity to bacteria growth. Rice straw treated by combined method after 72 hours enzyme saccharification could produce 85.3% and 75.4% reducing sugar, which is better than alkali-treatment and untreated rice straw, and after five times reuse still keep 83% and 93.4% relative to the first time. Compared to untreated rice straw, combined method can effective increase Yp/s from 0.044 to 0.178 and 0.198.

並列關鍵字

ionic liquids ； pretreatment ； lignocellulose

參考文獻

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