Being the most abundant carbon-containing terrestrial biopolymer, lignocellulose serves as one of the best candidate feedstocks for biofuel production. The current cost-ineffective method for lignocellulose pretreatment is one of the major barriers that hinder the development of biofuel production. This leads to an exploration in the potential application of lignocellulolytic enzymes in this biorefinery process. Taking advantage of the strong activity of ligninolytic enzymes in L. edodes, we aimed at cloning and heterologously expressing these enzymes. The present project applied a yeast expression system, Pichia pastoris, as a laboratory-scale platform for heterologous expression of one of our target ligninolytic enzymes, manganese peroxidase (MnP). We successfully cloned and expressed recombinant MnP. Its enzymatic activity was the highest when grown in the presence of hemoglobin. Our long-term goal is to establish a platform for the large-scale production of recombinant lignocellulotyic enzymes at low-cost, which would strengthen their application in biofuel production. / The shitake mushroom, Lentinula edodes, is one of the most commonly consumed edible mushrooms in Asian countries. It is a saprophyte that naturally colonizes dead wood. As a member of wood-decaying white rot basidiomycete, L. edodes is able to depolymerize lignin and hydrolyze wood polysaccharides. However, the enzymatic mechanism for its lignocellulolytic system is poorly understood. Examination on the L. edodes genome and transcriptome revealed a unique lignocellulolytic system. L. edodes has a diverse enzymatic arsenal for lignin degradation. The enzymes include laccase, manganese peroxidase, cellobiose dehydrogenase and various lignin degrading auxiliary enzymes. When compared to another white rot fungus Phanerochaete chrysosporium, L. edodes possesses more hemicellulase- and pectinase-coding genes, and fewer genes encoding cellulases, suggesting that it preferentially attacks non-cellulosic polysaccharides. The transcription analysis on genes related to antioxidative mechanisms also offers insights to the oxidative stress encountered by mycelium during the free radical-mediated lignin degradation. / Kwok, Sze Wai. / Adviser: Hoi-Shan Kwan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 141-160). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344616 |
| Date | January 2009 |
| Contributors | Kwok, Sze Wai., Chinese University of Hong Kong Graduate School. Division of Life Sciences. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xii, 160 leaves : ill. (some col.)) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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