Impact of Lignin and Fiber Morphology on Endoglucanese Hydrolysis of Eucalypt Kraft Pulp
| Autor: | Fang-Jing Chen, 陳芳璟 |
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| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Roles played by fiber physical and chemical characteristics in enzymatic hydrolysis of cellulosic materials were investigated by analyzing the interaction between an endoglucanase complex and eucalypt kraft fibers. PFI refining was employed to create the difference of fiber size distribution and morphology. Oxygen delignification and bleaching were employed to prepare fibers with different lignin and pentosan contents. The enzyme accessibility was monitored by adsorption at 4oC and during hydrolysis at 40oC. Molecular weight changes and reducing sugar released were monitored for digestibility of the samples. Greater maximum adsorption capacities of the enzymes were shown for the pulps with shorter and wider fibers and more fine fractions after refining. Highest amount of enzyme was adsorbed onto fibers with the least lignin contents at 4oC. Fewer desorbed from fibers with higher lignin contents during hydrolysis at 40oC. For unrefined fibers, less molecular weight reductions were observed for fibers with higher lignin contents. However, extensive fibrillation by refining negated the effects of lignin on the action of endoglucanase, similar molecular weight reductions were observed for fibers with three different lignin contents. Refining could be able to expose more reaction sites on the fiber surface, hence the impacts of lignin and pentosan diminished during hydrolysis for refined fibers. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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