Download or read book Enzymatic Degradation of Cellulose by the Filamentous Fungus Neurospora Crassa written by Christopher Michael Phillips and published by . This book was released on 2011 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lignocellulosic biomass is an abundant renewable resource that can be used as a feedstock for production of second-generation biofuels. Currently, the bottleneck to generation of such fuels lies in the expensive and technically challenging process for converting biomass to fermentable sugars. Filamentous fungi are efficient at depolymerizing plant biomass. These fungi are also used for the production of industrial enzymes due to their ability to secrete large quantities of enzymes. The filamentous fungus Neurospora crassa is a genetically tractable model organism and a proficient degrader of plant biomass. In this dissertation, the enzymatic depolymerization of cellulose by Neurospora crassa was investigated using a combination of quantitative proteomics, genetics, and biochemistry. Chapter 1 is an introduction to lignocellulosic biomass and the organisms and enzymes that degrade it. In Chapter 2, a quantitative proteomic approach was taken to characterize the secretome of Neurospora crassa during growth on microcrystalline cellulose. Depolymerization of cellulose occurs by endoglucanases that hydrolyze internal glycosidic bonds and cellobiohydrolases that hydrolyze cellobiose from the reducing or non-reducing chain ends of cellulose. In addition to these canonical cellulases, a number of other proteins were quantified including a beta-glucosidase, a cellobiose dehydrogenase (CDH), and glycosyl hydrolase family 61 (GH61) enzymes. The beta-glucosidase and 3 cellulases were purified and biochemically characterized. While these 4 enzymes represent more than 85% of the cellulase in the secretome, they were significantly impaired in their rate of cellulose degradation relative to the complete set of enzymes in the secretome. This result suggested that proteins other than canonical cellulases may be important in cellulose depolymerization by fungi. The deletion of a gene encoding cellobiose dehydrogenase in N. crassa is described in Chapter 3. Cellobiose dehydrogenase (CDH) catalyzes the oxidation of cellobiose to cellobionolactone, but the biological function of this protein was previously unknown. Deletion of cdh-1 reduced cellulase activity 37-49% and addition of purified CDHs to the cdh-1 deletion strain resulted in a 1.6 to 2.0-fold stimulation in cellulase activity. The stimulatory effect of CDH required the presence of molecular oxygen and other secreted metalloproteins. The discovery that cellobiose dehydrogenase plays an integral role in degradation of cellulose marked a significant shift from previous models centered on the degradation of cellulose by mixtures of glycosyl hydrolases. To determine the molecular mechanisms by which CDH can enhance cellulase activity, a fractionation strategy was employed as described in Chapter 4 to identify synergistic metalloproteins in the N. crassa secretome. CDH was shown to enhance cellulose degradation by coupling the oxidation of cellobiose to the reductive activation of copper-dependent polysaccharide monooxygenases (PMOs), previously called GH61 enzymes. These enzymes catalyze the insertion of oxygen into C-H bonds adjacent to the glycosidic linkage and facilitate elimination of the adjacent carbohydrate moiety. A further discussion of the mechanism of copper-dependent PMOs is discussed in Chapter 5. Here, the action of different PMOs was shown to be regiospecific resulting in oxidized products modified at C1 on the reducing end or C4 on the non-reducing end. CDHs and proteins related to the PMOs are found in cellulolytic species throughout the fungal kingdom. When added to mixtures of cellulases, these proteins enhance cellulose depolymerization and could significantly reduce the cost of biofuel production. In chapter 6, the development of N. crassa as a host for recombinant expression of secreted enzymes is described. Expression of the endocellulase GH5-1 is used to complement the phenotype of a gh5-1 deletion strain. Experiments with GH5-1 fused to GFP (green fluorescent protein) were used to visualize the binding of this endocellulase to plant biomass. Additional applications for N. crassa as an expression host for fundamental studies of biomass depolymerizing enzymes are described.
Download or read book Contribution of Oxidative Enzymes to the Degradation of Cellulose by Filamentous Fungi written by William Templeton Beeson and published by . This book was released on 2011 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cost of cellulose degrading enzymes is still a major barrier to the economical production of liquid fuels from lignocellulose. Fungi play a central role in the degradation of plant biomass in terrestrial environments. They use a wide variety of secreted enzymes to break down biopolymers present in the plant cell wall. Here I report on the mechanisms of cellulose degradation used by Neurospora crassa, a model genetic organism, and Myceliopthora thermophila, a thermophilic fungus. Enzymes important for the degradation process were identified using a combination of transcriptomics, proteomics, genetics, and biochemistry. A key result from this work is that, in N. crassa and many other fungi, oxidative enzymes play a critical role in the depolymerization of cellulose. In contrast to the accepted models of oxidative cellulose degradation, via non-specific hydroxyl radical species, I found that in N. crassa, an oxidoreductase and several copper oxidases bind to cellulose and hydroxylate the substrate at specific positions leading to cleavage of the glycosidic bonds. This mode of action is orthogonal to that of traditional hydrolases and if used optimally in conjunction with other cellulases, could reduce the required enzyme loading for lignocellulose saccharification by 2-4 fold.
Download or read book Mechanisms and Regulation of Cellulose Degradation by Fungal Enzymes written by Padma Rekha Gunda and published by . This book was released on 2011 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid fuels derived from plant biomass have the potential to contribute to sustainability efforts. However, the conversion of plant biomass is very difficult due to its complex nature. Cellulose, the primary component of plant cell walls, is a recalcitrant polysaccharide comprised of glucose. In nature, various fungi and bacteria enzymatically depolymerize cellulose for consumption. Understanding how cellulases are produced and function will be invaluable to the realization of cellulosic biofuels. The work here describes how a prominent cellulase interacts with cellulose during depolymerization, and how the cellulolytic fungus Neurospora crassa in part signals for the production of cellulase enzymes. The interactions of cellulases with cellulose are not well understood due to the recalcitrance and heterogeneity of the solid substrate. Cellobiohydrolase I, the most prominent cellulase in many fungal systems, was fluorescently labeled and monitored on the surface of crystalline cellulose. Four classes of behaviors were observed for this enzyme on the surface of cellulose: productive and linear movement, nonproductive surface diffusion, stationary, and transient association. In parallel, changes to the surface of crystalline cellulose were observed with atomic force microscopy to characterize how this enzyme modifies its substrate after degradation. The processes that initiate cellulase induction in Neurospora crassa have yet to be identified. A screen of deletion strains grown on cellulose was performed to isolate regulators of cellulase production. A kinase (NCU07399) was identified as a regulator of the transcriptional activation of several cellulase genes. Deletion of this kinase in Neurosporareduces the upregulation of cellulases by as much as 50-fold and also induces the secretion of a metalloprotease. The results here provide a basis for exploring the pathways involved in N. crassa cellulase production.
Download or read book Induction of Lignocellulose Degrading Enzymes in Neurospora Crassa by Cellodextrins written by Elizabeth A. Znameroski and published by . This book was released on 2012 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neurospora crassa colonizes burnt grasslands in the wild and metabolizes both cellulose and hemicellulose from plant cell walls. When switched from a favored carbon source such as sucrose to cellulose, N. crassa dramatically upregulates expression and secretion of a wide variety of genes encoding lignocellulolytic enzymes. However, the means by which N. crassa and other filamentous fungi sense the presence of cellulose in the environment remains unclear. Here, I show that a N. crassa mutant carrying deletions of two genes encoding predicted extracellular [beta]-glucosidase enzymes and one intracellular [beta]-glucosidase enzyme (d3[beta]G) lacks [beta]-glucosidase activity, but efficiently induces cellulase gene expression and cellulolytic activity in the presence of cellobiose as the sole carbon source. These data indicate that cellobiose, or a modified version of cellobiose, functions as an inducer of lignocellulolytic gene expression and activity in N. crassa. In addition, I have identified two cellodextrin transporters involved in sensing cellulose. A N. crassa mutant carrying deletions for both transporters is unable to induce cellulase gene expression in response to crystalline cellulose. Furthermore, a mutant lacking [beta]- glucosidase enzymes and transporters (d3[beta]GdT) does not induce cellulase gene expression in response to cellobiose.
Download or read book Biochemistry and Genetics of Cellulose Degradation written by Jean-Paul Aubert and published by . This book was released on 1988 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reviews basic research into the biochemistry and genetics of lignocellulose biodegradation; the breakdown of cellulose containing products utilizing microorganisms. This topic has received much attention of late because of possibilities for the biotechnology industry and because it is hoped that advances in the field will make a contribution to the energy crisis by utilizing biomass. However, there remains a good deal of basic research still to be done before full exploitation can be achieved.
Download or read book Fungal Cellulolytic Enzymes written by Xu Fang and published by Springer. This book was released on 2018-08-31 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides an overview of the current knowledge on cellulolytic enzymes and their applications. It summarizes the mechanisms of synthesis and hydrolysis of cellulolytic enzymes, industrial fungal strains, genetic engineering of fungal strains and application of cellulolytic enzymes. This book will be a useful reference for researchers and bioengineering experts engaged in lignocelluloses biodegradation, biomass utilization, enzyme production and fungal molecular biology.
Download or read book Green Fuels Technology written by Carlos Ricardo Soccol and published by Springer. This book was released on 2016-08-10 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents key recent developments in biofuel policy, products, processes, patents and innovative technologies. It presents several case studies, which maximize reader insights into how innovative green energy technologies can be implemented on an industrial scale, with illustrations, photos and new approaches. It also analyzes in detail several different technological aspects of the research into and production of green fuels from the first, second and third generation, such as, bioethanol, biogas, biohydrogen, biobutanol, biofuels from pyrolysis, and discusses their economic and environmental impacts. A new source of information for engineers, technicians and students involved in production and research in the biofuels sector, this book also provides a valuable resource for industry, covering the current and future status of biofuels.
Download or read book Pharmacoepigenetics written by Ramón Cacabelos and published by Academic Press. This book was released on 2019-06-04 with total page 986 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pharmacoepigenetics provides a comprehensive volume on the role of epigenetics and epigenomics in drug discovery and development, providing a detailed, but accessible, view of the field, from basic principles, to applications in disease therapeutics. Leading international researchers from across academia, clinical settings and the pharmaceutical industry discuss the influence of epigenetics and epigenomics in human pathology, epigenetic biomarkers for disease prediction, diagnosis, and treatment, current epigenetic drugs, and the application of epigenetic procedures in drug development. Throughout the book, chapter authors offer a balanced and objective discussion of the future of pharmacoepigenetics and its crucial contribution to the growth of precision and personalized medicine. - Fully examines the influence of epigenetics and epigenomics in human pathology, epigenetic biomarkers for disease prediction, diagnosis, treatment, current epigenetic drugs and the application of epigenetic procedures in drug development - Features chapter contributions from leading international researchers in academia, clinical settings and the pharmaceutical industry - Instructs researchers, students and clinicians on how to better interpret and employ pharmacoepigenetics in drug development, efficiency and safety - Provides a balanced and objective discussion of the future of pharmacoepigenetics and its crucial role in precision medicine
Download or read book Handbook of Fungal Biotechnology written by Dilip K. Arora and published by CRC Press. This book was released on 2003-12-17 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook of Fungal Biotechnology offers the newest developments from the frontiers of fungal biochemical and molecular processes and industrial and semi-industrial applications of fungi. This second edition highlights the need for the integration of a number of scientific disciplines and technologies in modern fungal biotechnology and reigns as
Download or read book Xylanolytic Enzymes written by Pratima Bajpai and published by Academic Press. This book was released on 2014-02-03 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Xylanolytic Enzymes describes the enzyme structure and its interaction with plant cell walls, the properties and production of different enzymes and their application, and the knowledge gathered on the hydrolysis mechanism of hemicellulose. The knowledge gathered about the hydrolysis mechanism of the hemicelluloses, especially xylans, has greatly promoted the rapid application of these enzymes in new areas. Recently there has been much industrial interest in xylan and its hydrolytic enzymatic complex, as a supplement and for the manufacturing of food, drinks, textiles, pulps and paper, and ethanol; and in xylitol production as a fermentation substrate for the production of enzymes. This book describes xylan as a major component of plant hemicelluloses. - Presents a thorough overview of all aspects of xylanolytic enzymes - Gives up-to-date authoritative information and cites pertinent research - Includes studies on xylanase regulation and synergistic action between multiple forms of xylanase
Download or read book Sustainable Degradation of Lignocellulosic Biomass written by Anuj Chandel and published by BoD – Books on Demand. This book was released on 2013-05-15 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides important aspects of sustainable degradation of lignocellulosic biomass which has a pivotal role for the economic production of several value-added products and biofuels with safe environment. Different pretreatment techniques and enzymatic hydrolysis process along with the characterization of cell wall components have been discussed broadly. The following features of this book attribute its distinctiveness: This book comprehensively covers the improvement in methodologies for the biomass pretreatment, hemicellulose and cellulose breakdown into fermentable sugars, the analytical methods for biomass characterization, and bioconversion of cellulosics into biofuels. In addition, mechanistic analysis of biomass pretreatment and enzymatic hydrolysis have been discussed in details, highlighting key factors influencing these processes at industrial scale.
Download or read book Chitin and Chitosan written by Lambertus A. M. van den Broek and published by John Wiley & Sons. This book was released on 2020-01-21 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers a comprehensive guide to the isolation, properties and applications of chitin and chitosan Chitin and Chitosan: Properties and Applications presents a comprehensive review of the isolation, properties and applications of chitin and chitosan. These promising biomaterials have the potential to be broadly applied and there is a growing market for these biopolymers in areas such as medical and pharmaceutical, packaging, agricultural, textile, cosmetics, nanoparticles and more. The authors – noted experts in the field – explore the isolation, characterization and the physical and chemical properties of chitin and chitosan. They also examine their properties such as hydrogels, immunomodulation and biotechnology, antimicrobial activity and chemical enzymatic modifications. The book offers an analysis of the myriad medical and pharmaceutical applications as well as a review of applications in other areas. In addition, the authors discuss regulations, markets and perspectives for the use of chitin and chitosan. This important book: Offers a thorough review of the isolation, properties and applications of chitin and chitosan. Contains information on the wide-ranging applications and growing market demand for chitin and chitosan Includes a discussion of current regulations and the outlook for the future Written for Researchers in academia and industry who are working in the fields of chitin and chitosan, Chitin and Chitosan: Properties and Applications offers a review of these promising biomaterials that have great potential due to their material properties and biological functionalities.
Download or read book Fungi written by Kevin Kavanagh and published by John Wiley & Sons. This book was released on 2011-08-04 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fungi: Biology and Applications, Second Edition provides a comprehensive treatment of fungi, covering biochemistry, genetics and the medical and economic significance of these organisms at introductory level. With no prior knowledge of the subject assumed, the opening chapters offer a broad overview of the basics of fungal biology, in particular the physiology and genetics of fungi and also a new chapter on the application of genomics to fungi. Later chapters move on to include more detailed coverage of topics such as antibiotic and chemical commodities from fungi, new chapters on biotechnological use of fungal enzymes and fungal proteomics, and fungal diseases of humans, antifungal agents for use in human therapy and fungal pathogens of plants.
Download or read book Industrial Enzyme Applications written by Andreas Vogel and published by John Wiley & Sons. This book was released on 2019-10-28 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference is a "must-read": It explains how an effective and economically viable enzymatic process in industry is developed and presents numerous successful examples which underline the efficiency of biocatalysis.
Download or read book Microbial and Enzymatic Degradation of Wood and Wood Components written by Karl-Erik L. Eriksson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oil crisis during the 1970s turned interest towards the utilization of renewable resources and towards lignocellulosics in particular. The 1970s were also the cradle period of biotechnology, and the years when biotechnical utilization of lignocellulosic waste from agriculture and forestry gained priori ty. This was a logical conclusion since one of nature's most important biologi cal reactions is the conversion of wood and other lignocellulosic materials to carbon dioxide, water and humic substances. However, while biotechnology in other areas like medicine and pharmacology concerned production of expen sive products on a small scale, biotechnical utilization and conversion of ligno cellulosics meant production of inexpensive products on a large scale. Biotechnical utilization of lignocellulosic materials is therefore a very difficult task, and the commercial utilization of this technology has not progressed as rapidly as one would have desired. One reason for this was the lack of basic knowledge of enzyme mechanisms involved in the degradation and conversion of wood, other lignocellulosics and their individual components. There are also risks associated with initiating a technical development before a stable platform of knowledge is available. Several of the projects started with en thusiasm have therefore suffered some loss of interest. Also contributing to this failing interest is the fact that the oil crisis at the time was not a real one. At present, nobody predicts a rapid exhaustion of the oil resources and fuel production from lignocellulosics is no longer a high priority.
Download or read book Fungal Genetics in Plant Biomass Conversion written by Jiwei Zhang and published by Frontiers Media SA. This book was released on 2023-02-17 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fungal Cell Wall written by José Ruiz-Herrera and published by CRC Press. This book was released on 2016-04-19 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fungal Cell Wall: Structure, Synthesis, and Assembly, Second Edition is a compendium of information on the chemical structure, synthesis, and organization of the cell wall of fungi. Reviewing the past 20 years of research in the field, it discusses experimental evidence that demonstrates the role of the cell wall in the growth, development, morphog
