探討固態發酵自行生產纖維水解酵素用於分解稻稈及生產生質酒精之研究

王鵬榮(PENG-RONG WANG)

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(2015年)

摘要

近年來由於能源危機與石油價格波動，以農業廢棄物作為基質的生質酒精為研究議題漸受重視，也有需多文獻及研究成果，足以說明生質能源目前佔有重要的地位。
本研究透過固態發酵培養Aspergillus niger與Trichiderma reesei，大量生產纖維水解酵素，並於糖化步驟中提出有別於傳統的糖化方法。傳統的方法均為添加純化的纖維水解酵素，近年來亦有自行生產酵素的操作，且需經過粗製的純化與分離菌體的步驟。在本研究中提出藉由控制環境參數以省略分離純化的步驟，抑制菌體生長以及測試還原糖累積，達到減少成本的效果。在糖化的步驟發現纖維水解酵素活性為糖化步驟的主因，進而提出延長酵素活性的方法，使累積還原糖達到更好的效果。最後利用糖化後的發酵液讓Saccharomyces cerevisiae 進行酒精發酵。
由實驗結果顯示，本研究第一階段的Aspergillius niger與Trichoderma reesei共培養酵素液最大活性為0.54FPU/g sub，而在第二階段可以從2g稻稈糖化出的還原糖累積量為14.25g/L，水解效率達到64%，而在第三階段酒精發酵的酒精生產量為3.99g/L，轉化率為55%。

關鍵字

生質酒精 ； 發酵 ； 稻稈

並列摘要

In this study, agricultural waste—straws were hydrolyzed and used to replace the relatively expensive glucose or molasses in ethanol production ,and to reduce the cost of the fermentation process.
Solid-state fermentation was carried out with Trichoderma reesei RUT C-30 and Aspergillus niger BCRC 31130 co-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 0.62, 0.79 and 7.5 U/ml, respectively.
Hydrolysis process was carried out at 50°C for 48h ,with add to soymilk to reduce the cellulase inactivation ,and to get the highest cumulative sugar concentration of 14.25 g/L and the decomposition ratio of 64%.
Ethanol fermentation was carried out in a serum bottle with the sugar gain from hydrolysis and obtained the highest ethanol concentration of 3.99g/L.

參考文獻

1. Mosier, N., et al., Features of promising technologies for pretreatment of lignocellulosic biomass. Bioresource technology, 2005. 96(6): p. 673-686.

2. Gaykawad, S.S., et al., Pervaporation of ethanol from lignocellulosic fermentation broth. Bioresource technology, 2013. 129: p. 469-476.

3. Balat, M., Production of bioethanol from lignocellulosic materials via the biochemical pathway: a review. Energy conversion and management, 2011. 52(2): p. 858-875.

5. Sánchez, C., Lignocellulosic residues: biodegradation and bioconversion by fungi. Biotechnology advances, 2009. 27(2): p. 185-194.

6. Himmel, M.E., J.O. Baker, and R.P. Overend, Enzymatic conversion of biomass for fuels production. 1994: American Chemical Society Washington, DC.