| Summary: | 碩士 === 國立雲林科技大學 === 化學工程與材料工程系 === 106 === Sugarcane bagasse (SCB), a renewable ligonocellulosic resource, essentially consists of cellulose, hemicelluloses and lignin. SCB can be used to produce ethanol and many value-added products. Ethanol production from SCB requires three main steps, including pretreatment (improving the accessibility of cellulases enzymes), enzymatic hydrolysis (converting to fermentable sugars) and fermentation (producing ethanol). In this study, optimizations of alkaline pretreatment and hydrolysis of SBC by using a novel cellulases-complex with high β-glucosidase activity were investigated through the orthogonal experimental design. Results showed that concentration of NaOH was the most significant variable affecting hydrolysis yield of pretreated SCB, and the optimized pretreatment conditions were: NaOH concentration 5% (w/v), solid-to- liquid ratio 1:30, 100℃ and 80 min. In addition, 4% (w/v) pretreated SBC was hydrolyzed for 24 hr with the cellulases-complex, and the variables to be optimized were enzyme dosage, hydrolysis temperature and pH. The optimized hydrolysis conditions were: 1/10-fold diluted enzyme dosage, hydrolysis temperature 45 oC and hydrolysis pH 4.0. The glucose production yield after 24-hr enzymatic hydrolysis was about 98.7%. Moreover, a higher initial SCB concentration in the batch hydrolysis might result in lower hydrolysis yield because of mixing difficulty and serious product inhibition. Therefore, various fed-batch operating strategies were proposed to increase the hydrolysis yield. It was found that the glucose production yield after 24-hr hydrolysis could be significantly increased upto 97.7%, better than 8% SCB- batch hydrolysis (74%), for a fed-batch operation initiated with 4% SCB loading and simultaneously fed with enzyme and 1% SCB at 4, 8, 12 or 16 hr intervals.
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