- 學位論文
利用耐高溫酵母菌發酵纖維素及柳丁皮廢棄物之研究
Ethanol production from cellulose and orange peel using thermotolerant yeasts
摘要
本研究篩選耐高溫的酵母，利用纖維素為原料，添加纖維分解酵素，進行酒精發酵的研究。實驗分為兩個部分，第一部分為篩選耐高溫酵母菌，找出能夠於40~45℃條件下生長並產生酒精。第二部分則是將篩選出的酵母菌與纖維素及柳丁皮進行同步糖化發酵的實驗。 結果顯示所篩選的50株酵母菌當中，以Kluyveromyces marxianus菌屬之酵母菌耐熱性較佳，最後選擇編號K21的菌株，以 7.5% (w/v) alpha-cellulose為基質，AccelleraseTM 1000為纖維素水解酵素，分別在45℃與42℃進行同步糖化發酵實驗，結果顯示在45℃酵母的存活率下降，最後的酒精濃度為20 g/L，而在42℃的酵母存活率較高，酒精濃度為30g/L。 乾燥磨粉過的柳丁皮以AccelleraseTM 1000以及pectinase進行水解，分析水解物成份主要以葡萄糖、果糖、蔗糖為主。以柳丁皮進行同步糖化發酵，10%(w/v)的柳丁皮得到酒精濃度為17g/L，20%(w/v)的柳丁皮得到酒精濃度為33g/L。
並列摘要
In this study, we selected thermotolerant yeasts to produce ethanol from cellulose in the presence of cellulase. This study falled into two sections. The first section was try to find the thermotolerant yeast, which can grow at 40 – 45 ℃. The other section was using the thermotolerant yeast to produce ethanol from cellulose and orange peel waste by simultaneous saccharification and fermention. Among the fifty strains of thermotolerant yeast that we screened, the most thermotolerant were the Kluyveromyces marxianus genus yeasts. From those Kluyveromyces marxianus genus yeasts, we selected a yeast strain and called it “K21”. Ethanol production was carried out using 7.5 % (w/v) alpha-cellulose as substrate in the percent of AccelleraseTM 1000 and K21 yeast cells by simultaneous saccharification and fermentation (SSF) at 42, and 45 ℃, respectively. The results indicate that the viability at 42 ℃ was higher than at 45 ℃, and the maximum ethanol concentration were 30 g/L and 45g/L, at 42 ℃ and 45 ℃, respectively. The orange peel was dried in the 70 ℃ oven and then was ground into powders. Ethanol production was carried out in jar fermenter using orange peel as raw material in the presence of AccelleraseTM 1000, pectinase and K21 yeast cells by SSF. The results indicate that 10 % (w/v) orange peel resulted an ethanol concentration of 17 g/L, and the 20 % (w/v) orange peel led to an ethanol concentration of 33 g/L, respectively.