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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Use of stimulatory agents to enhance the production of bioactive mushroom exopolysaccharide by submerged fermentation: a mechanistic study. / CUHK electronic theses & dissertations collection / Digital dissertation consortium

January 2011 (has links)
All these results advance our understanding on how stimulatory agents can be used to increase the production of useful metabolites by submerged fermentation of mushroom mycelium and indicate its potential biotechnological applications. / By use of one- and two-dimensional gels in proteomic analysis, some functional mycelial proteins that were differentially expressed by the addition of Tween 80 were identified. The up-regulation of heat shock proteins might help to maintain cellular viability under environmental stress. A down-regulation of YALI0E34793p and an up-regulation of ATP citrate lyase isoform 2 might suppress the activity of TCA cycle and subsequently stimulated the EPS production. Up-regulation of fatty acid synthase alpha subunit FasA might promote the synthesis of long-chain fatty acids and their incorporation into the mycelial cell membranes. Up-regulation of mitogen-activated protein kinase might facilitate the signal transduction in these processes. / The BPS, a highly branched glucomannan produced by the addition of Tween 80 in the fermentation broth of PTR mycelium had similar carbohydrate and protein content, monosaccharide composition and glycosidic linkages except by having a significantly lower molecular weight when compared to those of the control. Both BPS, with and without addition of Tween 80, could significantly inhibit (p < 0.05) the in vitro growth of a chronic myelogenous leukemia cells K562 in a dose dependent manner, with an estimated IC50 value of 43.7 and 47.6 microg/mL, respectively. / The effects of different kinds of stimulatory agents including fatty acids, surfactants and organic solvents were compared. The optimum results were achieved when 3.0 g/L Tween 80 was added to the fermentation broth on the 5th day of the fermentation, to give a maximum increase of 51.3 and 41.8% (p < 0.05) in the yield of mycelial biomass and BPS production, respectively. / The underlying mechanisms by which Tween 80 could increase the mycelial growth and EPS production in PTR were investigated by three novel approaches including changes in the nutrient uptake by mycelium, the morphology of mycelial pellets, and the fatty acid composition in the mycelial cell membrane. Firstly, the addition of Tween 80 significantly increased the glucose consumption rate by the mycelium, implying that the efficiency of nutrient uptake from the fermentation broth was enhanced. Secondly the addition of Tween 80 could extend the growth period of the mycelium possibly by maintaining the intact structure of the mycelial pellets and preventing its disintegration caused by shear stress in the fermentation system. Thirdly, the addition of Tween 80 could increase the incorporation of oleic acid which was a constituent of Tween 80 itself into the mycelial cell membrane of PTR, altering its fatty acid composition and increase the cell membrane permeability. The first two results explained the enhancement in the mycelial growth and EPS production while the last one was related to the extracellular transport of EPS to the fermentation broth. / This study aimed at comparing the effectiveness in the use of stimulatory agents with different chemical structures for enhancing the production of mycelial biomass and exopolysaccharide (BPS) by submerged fermentation of an edible mushroom Pleurotus tuber-regium (PTR). The chemical characteristics and antitumor activity of the BPS produced with and without the addition of the most effective stimulatory agent (Tween 80 which is a permitted food additive) were also compared. The underlying mechanisms by which Tween 80 could exert its effect on the mushroom mycelium were investigated by using chemical methods and microscopic techniques as well as proteomic analysis. / Zhang, Bobo. / Adviser: Chi Keung Peter Cheung. / Source: Dissertation Abstracts International, Volume: 73-08, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 132-156). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
2

Laccase production by pleurotus sajor-caju and flammulina velutipes.

January 1994 (has links)
Lo Sze Chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 100-113). / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.iv / List of Figures and Tables --- p.vii / Abbreviations --- p.xii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Edible mushrooms --- p.1 / Chapter 1.1.1 --- Pleurotus sajor-caju --- p.1 / Chapter 1.1.2 --- Flammulina velutipes --- p.2 / Chapter 1.2 --- Lignocellulose and phenolic monomers --- p.4 / Chapter 1.2.1 --- Sources of phenolic monomers --- p.4 / Chapter 1.2.2 --- Toxicity of phenolic monomers --- p.10 / Chapter 1.3 --- Fungal laccases --- p.13 / Chapter 1.3.1 --- Occurrence --- p.13 / Chapter 1.3.2 --- Laccase reaction --- p.14 / Chapter 1.3.3 --- Physiological functions --- p.18 / Morphogenesis --- p.18 / Pathogenicity --- p.19 / Lignin degradation --- p.20 / Chapter 1.4 --- Purpose of study --- p.22 / Chapter 2. --- Materials and Methods --- p.24 / Chapter 2.1 --- General --- p.24 / Chapter 2.1.1 --- Organisms --- p.24 / Chapter 2.1.2 --- Culture medium --- p.24 / Chapter 2.1.3 --- Addition of phenolic compounds --- p.24 / Chapter 2.2 --- Effect of phenolic monomers on the growth of mushroom mycelium on agar plates --- p.25 / Chapter 2.3 --- Effect of phenolic monomers on the production of fungal biomass in liquid culture --- p.25 / Chapter 2.4 --- Effect of phenolic monomers on the extracellular laccase produced by P. sajor-caju and F. velutipes --- p.26 / Chapter 2.5 --- Assay of laccase activity --- p.26 / Chapter 2.6 --- Electrophoresis patterns of laccase proteins --- p.27 / Chapter 2.6.1 --- Non-denaturing polyacrylamide gel electrophoresis --- p.27 / Chapter 2.6.2 --- Localization of laccase activity --- p.27 / Chapter 2.7 --- Purification of extracellular laccases from P. sajor-caju --- p.28 / Chapter 2.7.1 --- Inoculum preparation --- p.28 / Chapter 2.7.2 --- Culture conditions --- p.28 / Chapter 2.7.3 --- Concentration of culture supernatant --- p.29 / Chapter 2.7.4 --- Ammonium sulphate fractionation --- p.29 / Chapter 2.7.5 --- Anion exchange chromatography --- p.29 / Chapter 2.7.6 --- Preparative polyacrylamide gel electrophoresis --- p.30 / Chapter 2.7.7 --- Protein detection and quantification --- p.30 / Chapter 2.8 --- Characterization of Laccase Protein --- p.31 / Chapter 2.8.1 --- "Effect of pH, temperature and substrate concentration" --- p.31 / Chapter 2.8.2 --- Effect of inhibitors --- p.32 / Chapter 2.8.3 --- Determination of isoelectric point --- p.32 / Chapter 2.8.4 --- Determination of molecular weight --- p.33 / Chapter 3. --- Results --- p.34 / Chapter 3.1 --- Effect of phenolic monomers on the growth of P. sajor-caju and F. velutipes --- p.34 / Chapter 3.1.1 --- P. sajor-caju --- p.34 / Chapter 3.1.2 --- F. velutipes --- p.38 / Chapter 3.2 --- Effect of phenolic monomers on laccase production by P. sajor-caju and F. velutipes --- p.41 / Chapter 3.2.1 --- P. sajor-caju --- p.45 / Chapter 3.2.2 --- F. velutipes --- p.49 / Chapter 3.3 --- Electrophoretic patterns of extracellular laccase --- p.53 / Chapter 3.3.1 --- P. sajor-caju --- p.53 / Chapter 3.3.2 --- F. velutipes --- p.56 / Chapter 3.4 --- Purification of laccase protein from P. sajor-caju --- p.58 / Chapter 3.4.1 --- Separation of laccase proteins --- p.58 / Chapter 3.4.2 --- Purification of laccase IV --- p.59 / Chapter 3.5 --- Characterization of laccase IV from P. sajor-caju --- p.64 / Chapter 3.5.1 --- Optimum temperature and thermostability --- p.64 / Chapter 3.5.2 --- Optimum pH and pH stability --- p.67 / Chapter 3.5.3 --- Substrate concentration --- p.70 / Chapter 3.5.4 --- Effect of inhibitors --- p.74 / Chapter 3.5.5 --- Isoelectric point --- p.74 / Chapter 3.5.6 --- Molecular weight --- p.74 / Chapter 4. --- Discussion --- p.78 / Chapter 4.1 --- Phenolic monomers and the growth of P. sajor-caju and F. velutipes --- p.78 / Chapter 4.2 --- Phenolic monomers and laccase production by P. sajor- caju and F. velutipes --- p.81 / Chapter 4.3 --- Electrophoretic patterns of laccase proteins --- p.83 / Chapter 4.4 --- Physiological functions of laccase --- p.85 / Chapter 4.5 --- Purification of selected laccase protein from P. sajor-caju --- p.88 / Chapter 4.6 --- Properties of laccase IV from P. sajor-caju --- p.89 / Chapter 4.6.1 --- Optimum temperature and thermostability --- p.89 / Chapter 4.6.2 --- Optimum pH and pH stability --- p.90 / Chapter 4.6.3 --- Effect of inhibitors --- p.92 / Chapter 4.6.4 --- Km --- p.93 / Chapter 4.6.5 --- Isoelectric point --- p.94 / Chapter 4.6.6 --- Molecular weight --- p.94 / Chapter 4.7 --- Future works --- p.96 / Chapter 5. --- Conclusion --- p.98 / Chapter 6. --- References --- p.100
3

Comparison of lignocellulose-degrading enzymes in lentinus edodes, pleurotus sajor-caju and volvariella volvacea.

January 1993 (has links)
Cai Yi Jin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 118-128). / Chapter 1. --- Introduction / Chapter 1.1 --- Importance and Cultivation history of edible mushroom --- p.1 / Chapter 1.2 --- Variety and structure of growth substrates for mushroom --- p.4 / Chapter 1.3 --- Mushroom growth and substrate-degrading enzymes --- p.8 / Chapter 1.4 --- Purpose of study --- p.15 / Chapter 2. --- Methods and Materials / Chapter 2.1 --- Organisms --- p.17 / Chapter 2.2 --- Media --- p.17 / Chapter 2.3 --- Culture conditions --- p.21 / Chapter 2.3.1 --- Growth temperature --- p.21 / Chapter 2.3.2 --- Growth Studies --- p.21 / Chapter 2.3.2.1 --- Effect of pH on mycelial growth --- p.21 / Chapter 2.3.2.2 --- Effect of different carbon sources on mycelial growth --- p.21 / Chapter 2.3.2.3 --- Effect of lignin-related phenolic monomers and tannin derivatives on fungal growth --- p.22 / Chapter 2.3.3 --- Culture conditions for production of extracellular enzymes --- p.23 / Chapter 2.3.3.1 --- Tyrosinase --- p.23 / Chapter 2.3.3.2 --- Laccase --- p.23 / Chapter 2.3.3.3 --- Manganese-dependent Peroxidase and Lignin Peroxidase --- p.23 / Chapter 2.3.3.4 --- Cellulytic and Xylanolytic enzymes --- p.24 / Chapter 2.3.3.5 --- Lipase --- p.25 / Chapter 2.3.4 --- Culture conditions for studying properties of cellulases of V. volvacea --- p.26 / Chapter 2.3.4.1 --- CMCase --- p.26 / Chapter 2.3.4.2 --- "CMCase, FPase and β-Glucosidase" --- p.26 / Chapter 2.3.4.3 --- β-Glucosidase --- p.26 / Chapter 2.4 --- Enzyme assay --- p.27 / Chapter 2.4.1 --- Tyrosinase --- p.27 / Chapter 2.4.2 --- Laccase --- p.27 / Chapter a. --- o-Tolidine Method --- p.27 / Chapter b. --- ABTS Method --- p.28 / Chapter c. --- Syringaldazine Method --- p.28 / Chapter 2.4.3 --- Lignin peroxidase --- p.29 / Chapter 2.4.4 --- Manganese-dependent peroxidase --- p.29 / Chapter 2.4.5 --- Exoglucanase (avicelase) --- p.30 / Chapter 2.4.6 --- Endoglucanase (carboxymethylcellulase or CMCase) --- p.31 / Chapter 2.4.7 --- Filter paper digesting enzyme (FPase) --- p.32 / Chapter 2.4.8 --- P-Glucosidase --- p.32 / Chapter 2.4.9 --- Xylanase --- p.34 / Chapter 2.4.10 --- β-Xylosidase --- p.34 / Chapter 2.4.11 --- Lipase --- p.36 / Chapter 2.5 --- Other analytical methods --- p.36 / Chapter 2.5.1 --- Determination of phenol oxidase activity by the Bavendamm reaction --- p.36 / Chapter 2.5.2 --- Qualitative evaluation of CMCase by Congo red staining --- p.37 / Chapter 2.5.3 --- Effect of phenolic monomers and tannic acid on CMCase activity of V. volvacea --- p.38 / Chapter 2.5.4 --- Protein determination --- p.39 / Chapter 2.5.5 --- Non-denaturing gel electrophoresis pattern of fungal laccases --- p.39 / Chapter 2.6 --- Chemicals --- p.39 / Chapter 3. --- Results / Chapter 3.1 --- Growth and Nutritional characteristics --- p.44 / Chapter 3.1.1 --- Fungal growth on defined and non-defined culture media --- p.44 / Chapter 3.1.2 --- Effect of carbon source on fungal --- p.45 / Chapter 3.1.3 --- Effect of pH on fungal growth --- p.45 / Chapter 3.2 --- Effect of lignin-related phenolic monomers and tannin derivatives on fungal growth --- p.45 / Chapter 3.2.1 --- Effect of lignin-related phenolic monomers on fungal growth --- p.45 / Chapter 3.2.2 --- Effect of tannin derivatives on fungal growth --- p.61 / Chapter 3.3 --- Phenol Oxidase --- p.67 / Chapter 3.3.1 --- Phenol oxidase --- p.67 / Chapter 3.3.1.1 --- Guaiacol-reacting enzyme --- p.67 / Chapter 3.3.1.2 --- o-Anisidine oxidizing enzyme --- p.68 / Chapter 3.3.2 --- Tyrosinase --- p.69 / Chapter 3.3.3 --- Laccase --- p.69 / Chapter 3.3.3.1 --- "Laccase detected by o-Tolidine, ABTS Syringaldazine" --- p.69 / Chapter 3.3.3.2 --- Effect of pH on laccase activity --- p.69 / Chapter 3.4 --- Lignin-Transforming Enzymes --- p.73 / Chapter 3.4.1 --- Lignin peroxidase (LP) --- p.73 / Chapter 3.4.2 --- Manganese-dependent peroxidase (MnP) --- p.74 / Chapter 3.5 --- Cellulases --- p.78 / Chapter 3.5.1. --- Cellulases of V. volvacea --- p.78 / Chapter 3.5.1.1 --- Qualitative estimation of cellulose-degrading enzymes of V. volvacea grown on different substrates --- p.78 / Chapter 3.5.1.2 --- Influence of pH and temperature --- p.79 / Chapter 3.5.1.3 --- Cellulolytic activities in cultures grown on cellulose --- p.83 / Chapter 3.5.1.4 --- Cellulolytic activities in cultures grown on paddy straw --- p.91 / Chapter 3.5.1.5 --- β-Glucosidase activity in cultures grown on cellobiose --- p.91 / Chapter 3.5.1.6 --- Effect of lignin-related phenolic monomers and tannic acid on CMCase of V. volvacea --- p.95 / Chapter 3.5.2 --- Cellulases of P.sajor-caju --- p.96 / Chapter 3.5.3 --- Cellulases of L. edodes --- p.96 / Chapter 3.6 --- Xylanase --- p.96 / Chapter 3.6.1 --- "Xylanase of V. volvacea, strain V34" --- p.96 / Chapter 3.6.2 --- Xylanase of P.sajor-caju --- p.100 / Chapter 3.6.3 --- Xylanase of L. edodes --- p.100 / Chapter 3.7 --- Lipase of V. volvacea --- p.103 / Chapter 4. --- Discussion / Chapter 4.1. --- Carbon nutrition and pH for fungal growth --- p.104 / Chapter 4.1.1 --- Carbon nutrition --- p.104 / Chapter 4.1.2 --- pH --- p.104 / Chapter 4.2 --- "Effect of lignin-related phenolic monomers and tannin derivatives on fungal growth of L. edodes, P. sajor-caju and V, volvacea" --- p.105 / Chapter 4.2.1 --- Lignin-related phenolic monomers --- p.105 / Chapter 4.2.2 --- Tannin derivatives --- p.107 / Chapter 4.3 --- "Production of phenoloxidases by V. volvacea, L. edodes and P. sajor-caju" --- p.108 / Chapter 4.3.1 --- Guaiacol- and Anisidine reacting enzymes and Tyrosinase --- p.108 / Chapter 4.3.2 --- Laccase --- p.109 / Chapter 4.4. --- "Lignin-degrading Enzymes of V. volvacea, P. sajor-caju and L. edodes" --- p.110 / Chapter 4.5. --- "Cellulolytic and Hemicellulolytic Activity of V. volvacea, P.sajor-caju and L. edodes" --- p.113 / References --- p.118 / Appendix1 --- p.129

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