衣康酸(Itaconic acid)為一種用途廣泛的化學物，常被作為單體應用於製造塑膠、樹脂及橡膠等製品，也常被作為添加劑用於除草劑、乳化劑及高分子螯合劑等，是一種應用價值高並且具有發展潛力的一種化學物質。但目前的生產流程陷入瓶頸，原因是作為原料的葡萄糖成本過高，限制了衣康酸的經濟價值發展，因此若能找尋到較為便宜的原料以生產衣康酸，勢必可以解決這個問題，使衣康酸的經濟價值提高，能夠被更進一步的廣泛利用。 台灣早期為一個農業為主的國家，水道為台灣的第一大宗作物，每年約產生300萬噸的廢棄稻稈，若能利用這些屬於木質纖維材料的廢棄物—稻稈，並使用菌種生產脂纖維酵素做分解，將之做為原料生產衣康酸，則可以大幅降低衣康酸的生產成本，達到節省成本的目的。 本研究即是，利用黃豆加鹼處理過後之稻稈為原料，分別培養接種Aspergillus niger及Trichoderma ressei進行固態發酵，結束後將發酵殘餘物以適當比例做混合，添加檸檬酸緩衝溶液進行萃取，可得到三種纖維水解酵素之最高酵素濃度為3.88、3.95及4.11 U/ml，並發現使用稻稈作為誘導劑，可提升月46%的酵素產量。 接下來，將所得固液混合物，不經過繁瑣的過濾、濃縮等步驟，直接於攝氏50度下進行水解反應，可得最高的還原醣濃度為25.16 g/L。並發現酵素濃度高於1.3 U/ml時，可大幅提升水解效果。最後，將所得醣類進行衣康酸發酵，可得最高之衣康酸濃度為2.89g/L，轉化率為 23.1%。 ;Biotechnologically produced itaconic acid (IA) is a promising organic acid with a wide range of applications. But the cost problem of the raw material limited its capability of newer and wider applications. In this study, agricultural waste—straws were hydrolyzed and used to replace the relatively expensive glucose or molasses in IA production. Solid-state fermentation was carried out with Trichoderma ressei Rut C-30 and Aspergillus niger BCRC 31130 separated-cultured at 28°C. 7.5ml/g sub of 50mM citric acid buffer solution were used to extract enzyme from SSF residual. The crude enzyme without any purification and concentration with the highest enzyme activity of exoglucanase, endoglucanase and β-glucosidase was 3.88, 3.95 and 4.11 U/ml, respectively. Using straws as precursor could increase 46% of the enzyme yield. Hydrolysis was carried out at 50°C for 72h to get the highest cumulative sugar concentration of 25.16 g/L and the decomposition ratio of 88.1%. Additionally, we found enzyme activity of 1.3 U/ml for three kinds of cellulases was needed to promote the decomposition ratio dramatically. IA fermentation was carried out in a 2-L airlift fermenter with the sugar gain from hydrolysis and obtained the highest IA concentration of 2.89g/L. The results showed the feasibility of using straws as a replacement of molasses or glucose to decrease the cost of IA production, and it’s a valuable and potential subject worth of putting effort in.
