Wet Oxidative Steam Explosion of Peanut Vines for the Production of Xylo-oligosaccharides and Enhancement of Enzymatic Saccharification
| Autor: | Wan-Yi Chu, 曲婉儀 |
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| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Peanut is an important crop in the coastal areas of Taiwan, but the resulting peanut vines have limited uses so far. In order to fully utilize the peanut vines, we investigated the clean fractionation of peanut vines using the wet-oxidative (WO) steam explosion technology. In this study, peanut vines were subjected to WO steam explosion at various temperatures and residence times, in order to determine the optimal extraction condition for xylo-oligosaccharides. The WO steam explosion was performed at a constant oxygen pressure of 300 kPa (absolute at room temperature), while the reaction temperature ranged from 195 to 210℃, and the residence time from 5 to 25 min. The highest extraction yield of xylo-oligosaccharides, 36%, occurred at the WO steam explosion condition of 195℃, 15 min. The peanut vines steam-exploded at the optimal condition (195℃, 15 min) still contained high levels of lignin, so they were subjected to further alkaline treatments to remove lignin and improve enzymatic digestibility. An alkaline peroxide (AP) treatment (1~5％ w/w H2O2, pH 11.5, 80 ℃, 45 min, solid content of 2％ w/v) or a sodium hydroxide (NaHO) treatment (5~20％ NaOH, 80℃, 30 min, solid content of 4％ w/v) was used. The lignin removal rates increased with increasing NaOH concentration or H2O2 content, but the AP treatment was superior in both lignin removal and glucan recovery. The highest lignin removal rate obtained by the NaOH treatment was only 33.4%, whereas the AP treatment gave lignin removal rates as high as 81.7%. The enzymatic digestibility of treated peanut vines was found to be proportional to the removal rate of lignin. The highest enzymatic digestibility, 96%, was achieved at the 5% H2O2 condition. For the same AP treatment condition, the overall glucose yield after WO steam explosion, AP treatment, and enzymatic hydrolysis was 82%. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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