探討黃豆粉與溫度對Aspergillus terreus利用 酵素糖化稻稈生產衣康酸之影響

黃緬雄(Mian-Shiung Huang)

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

衣康酸 (Itaconic acid) 由於其具有特殊結構特性，因此被廣泛應用於民生工業上，用來製造人造纖維、樹酯及其他合成材料，甚至具有取代石化原料的潛力。Aspergillus terreus是目前已知具有較高衣康酸產率的真菌，由於過去主要針對衣康酸代謝途徑、pH值、通氣量及反應器等進行探討，但對於中高溫度以及農業廢棄物糖化還原糖之利用的研究較少，因此為本研究之重點。
首先以具有能生產較高活性之酵素的真菌，Trichoderma reesei利用經過鹼處理之稻稈作為誘導基質，在30°C下生產纖維水解酵素，相較於豆渣，以豆粉作為氮源能得到較高活性之酵素，得到內切、外切型纖維酵素及β-glucosidase酵素活性各為0.193 IU/mL、0.152 IU/mL、0.146 IU/mL，filter paper activity為0.754 FPU/mL。接著在稻稈糖化階段，若增加稻稈添加量則會使糖化效率降低，在50°C下糖化20、40及60 g/L的稻稈，得到各別19.14、32.88及45.13 g/L的還原糖，轉化率各為84.6、73.3及66.6%。
在衣康酸發酵實驗部分，若接菌量從10%增加至30%，衣康酸產率能夠被提高至0.826 g/L day，約3.4倍。相較於 (NH4)2SO4與CSL，以豆粉作為氮源，在40°C下進行衣康酸發酵能得到較高的衣康酸轉化率，在第8天能得到0.22 g/g的單位基質衣康酸轉化率 (Yp/s)，一康酸產率為1.28 g/L day。而初始葡萄糖為50 g/L時，若將豆粉濃度從2.1g/L減半至1.05g/L，葡萄糖與豆粉比率為47.62，衣康酸產率能被提高至1.57 g/L day，約提高22.7%，Yp/s為0.3 g/g。
最後透過限制氮源，以32 g/L糖化還原糖及0.67 g/L豆粉進行衣康酸發酵，得到菌量為6.16 g/L，衣康酸產率為0.4 g/L day，雖然相較於葡萄糖控制組略低，但還原糖也能有效的被利用。

關鍵字

衣康酸 ； 纖維水解酵素 ； 糖化 ； 稻稈 ； 黃豆

並列摘要

Itaconic acid (IA) has been declared to be one of the most promising and flexible building blocks derived from biomass, it is a monomer for the manufacturing of synthetic fibers, synthetic resins, plastics, rubbers or other polymeric materials.
A. terreus strains can achieve high product yields of IA by utilizing glucose. For several decades, some studies focus on metabolic pathway for IA production, pH, oxygen supply and bioreactor. However, the investigation of mesophilic or thermophilic temperature and utilizing rice straw for IA fermentation is deficient.
At present, T. reesei has been reported as the excellent cellulose producer. So first, the rice straw by alkaline pretreatment and soybean powder is used for cellulase production by T. reesei Rut C-30 at 30°C, the crude enzyme with the highest activity of CMCase, Avicelase and β-glucosidase was 0.193, 0.152 and 0.146 IU/mL, and the filter paper activity was 0.754 FPU/mL. The crude enzyme is used for saccharification of 20、40 and 60 g/L rice straw at 50°C, it obtains 19.14、32.88 and 45.13 g/L reducing sugar. The saccharification efficiency is 84.6、73.3 and 66.6% respectively.
In IA fermentation, the inoculum from 10 to 30% directly increases the IA productivity 3.4 times, it were obtained 0.826 g/L day. Using soybean powder as nitrogen source is better than (NH4)2SO4 and CSL at 40°C, the higher IA productivity and Yp/s, can be obtained 0.22 g IA/g glucose and 1.28 g/L day, respectively. If using half of 2.1 g/L soybean powder, the IA productivity can be increased to 1.57 g/L day and Yp/s is 0.3 g/g. At last, 32 g/L reducing sugar and 0.67 g/L soybean powder is used for IA production by nitrogen limitation, the IA productivity is 0.4 g/L day, it slightly less than the control group of glucose.

並列關鍵字

Itaconic acid ； Cellulase ； Saccharification ； Rice straw ； soybean

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