台灣每年從果汁加工廠所產生之農業廢棄物的產量相當可觀,本研究所使用的胡蘿蔔渣即為常見的加工廢棄物。傳統上胡蘿蔔渣可以直接作為牲畜之飼料或堆肥,其木質素含量低,主要以纖維素及半纖維素為主,適合直接拿來做為生質酒精的原料。 本研究初步使用纖維水解酵素AccelleraseTM 1000及pectinase兩種酵素對胡蘿蔔渣進行水解發現約有45~50% (w/w)的乾基能被發酵為酒精,水解出來的主要為葡萄糖與半乳糖。 在42℃利用胡蘿蔔渣進行同步糖化發酵(SSF),發現10% (w/v)胡蘿蔔渣可以產生18 g/L ethanol,胡蘿蔔渣對酒精的產率為18% (g-ethanol/g-carrot pomace)。若再饋入5% (w/v)胡蘿蔔渣,可以產生30 g/L ethanol,胡蘿蔔渣對酒精的產率為20% (g-ethanol/g-carrot pomace)。假若一次饋入10%胡蘿蔔渣,合計20%胡蘿蔔渣進行酒精發酵可以產生37 g/L ethanol。由於胡蘿蔔渣並不需要進行原料之預處理,可以直接用來生產酒精,因而在生質能源開發上可以省下不少成本。
The juice industry in Taiwan produces large amount of agricultural wastes. Carrot pomace, which is the subject of present study, is one common example. Traditionally, carrot pomace is used as pasture feed or fertilizer. In carrot pomace, lignin composes only a small fraction of lignocellulose, the major components of lignocellulose being cellulose and hemicellulose, which are easier for enzymatic saccharification than lignin. Two enzymes (AccelleraseTM 1000 and Pectinase) were found to hydrolyze 45% ~ 50% (w/w) of carrot pomace and the major hydrolysis products were glucose and galactose. Simultaneous Saccharification and Fermentation (SSF) at 42℃ was performed on 10% (w/v) carrot pomace and the process produced 18 g/L ethanol. The yield is 18% (g-ethanol/g-carrot pomace). Under fed-batch of additional 5% (w/v) of substrate, 30 g/L ethanol was produced. The yield is 20% (g-ethanol/g-carrot pomace). The further addition of ten percent carrot pomace would lead to ethanol fermentation and produce 37 g/L of ethanol. Due to the fact that no pre-treatment is required for carrot pomace, it is capable of manufacturing ethanol directly, thus reducing capital cost for developing alternative biomass energy.