Download or read book Single Molecule Study of Cellulase Hydrolysis of Crystalline Cellulose written by and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report seeks to elucidate the role of cellobiohydrolase-I (CBH I) in the hydrolysis of crystalline cellulose. A single-molecule approach uses various imaging techniques to investigate the surface structure of crystalline cellulose and changes made in the structure by CBH I.
Download or read book Single Molecule Study of Cellulase Hydrolysis of Crystalline Cellulose written by and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report seeks to elucidate the role of cellobiohydrolase-I (CBH I) in the hydrolysis of crystalline cellulose. A single-molecule approach uses various imaging techniques to investigate the surface structure of crystalline cellulose and changes made in the structure by CBH I.
Download or read book Cellulose Hydrolysis written by Liang-tseng Fan and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent economic trends, especially the worldwide decline in oil prices, and an altered political climate in the United States have combined to bring about major reductions in research on renewable energy resources. Yet there is no escaping the "facts of life" with regard to these resources. The days of inexpensive fossil energy are clearly numbered, the credibility of nuclear energy has fallen to a new low, and fusion energy stands decades or more from practical realization. Sooner than we may wish ,we will have to turn to renewable raw materials - plant "biomass" and, especially, wood - as significant suppliers of energy for both industry and everyday needs. It is therefore especially important to have a single, comprehensive and current source of information on a key step in any process for the technological exploitation of woody materials, cellulose hydrolysis. Further more, it is essential that any such treatment be unbiased with respect to the two methods - chemical and biochemical - for the breakdown of cellulose to sugars. Researchers on cellulose hydrolysis have frequently been chided by persons from industry, especially those individuals concerned with determining the economic feasibility of various technological alternatives. They tell us that schemes for the utilization of wood and other such resources fly in the face of economic realities.
Download or read book Investigating the Enzymatic Hydrolysis of Crystalline Cellulose Using Fluorescence Based Assays written by Navaneetha Santhanam and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydrolysis kinetics of bacterial microcrystalline cellulose (BMCC) by the cellulases of Thermobifida fusca was studied using fluorescence based assays in three ways. First, the binding of fluorescence-labeled Cel5A, Cel6B and Cel9A in ternary synergistic mixtures was assessed. A rapid high-throughput binding assay using microwell plates was developed to measure the bound fractions of the three cellulases at varying mole ratios of Cel6B and Cel9A, with Cel5A fixed at 10% of the total cellulase loading. This study revealed that the bound fractions of cellulases in ternary mixtures were additive, unlike the hydrolytic activity which was synergistic. Second, an experimental system was developed for the application of high resolution fluorescence microscopy to examine the binding of individual Cel5A, Cel6B and Cel9A to immobilized cellulose with varying morphologies. The immobilization technique allowed deposition of cellulose morphologies ranging from nanoscale cellulose fibers, to microscale cellulose fibril mats to sub-millimeter scale cellulose particles. Fluorescently labeled Cel5A, Cel6B and Cel9A were successfully integrated with fluorescently labeled cellulose to obtain a miniaturized reaction system which retained the intrinsic binding and hydrolytic capabilities of cellulases. Direct visualization of the binding behavior of individual cellulases on cellulose with different morphologies was achieved using this system which showed that the binding behavior depended strongly on the morphology and complexity of cellulose aggregates. Third, the significance of product inhibition by cellobiose as a rateretarding factor in the hydrolysis of BMCC by Cel9A and Cel9A-68, its construct lacking the family 2 cellulose binding module, was investigated. Fluorescently labeled BMCC was used as the substrate for an analysis of initial rates in the presence of exogenous cellobiose. Increasing cellobiose concentrations ranging from 1- 5mM were found to decrease the initial rate by 10 - 30% but increasing cellobiose concentrations from 5 to 60 mM did not cause a further decline in initial rates, clearly ruling out classical competitive inhibition as a possible mechanism. No definitive correlation was observed between binding and cellobiose concentrations for both enzymes indicating that the presence of cellobiose does not lead to significant enhancement or inhibition of binding.
Download or read book Advances in Enzymic Hydrolysis of Cellulose and Related Materials written by Elwyn T. Reese and published by Elsevier. This book was released on 2013-10-22 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Enzymic Hydrolysis of Cellulose and Related Materials documents the proceedings of a symposium held in March 1962. This book emphasizes the interests of contributors actively engaged in production and properties of the enzymes and cellulose decomposition. Despite the significance of enzymes, relatively little work has been done on this group of enzymes, which include cellulases, hemicellulases, xylanases, disaccharidases, and glycosidases. This compilation aims to have the biological aspects of celluloses and hemicelluloses recognized under the cellulose field, and the cellulases to be considered in future books about cellulose and wood. Other topics discussed in this selection include structural features of cellulose that influence its susceptibility to enzymatic hydrolysis; purification of cellulase and related enzymes; endwise degradation of cellulose; and applications for cellulases. This publication is beneficial to students and researchers conducting work on enzymes and cellulose decomposition.
Download or read book Biomass Recalcitrance written by Michael Himmel and published by Wiley-Blackwell. This book was released on 2008-06-23 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the connection between biomass structure, ultrastructure, and composition, to resistance to enzymatic deconstruction, with the aim of discovering new cost-effective technologies for biorefineries. It contains chapters on topics extending from the highest levels of biorefinery design and biomass life-cycle analysis, to detailed aspects of plant cell wall structure, chemical treatments, enzymatic hydrolysis, and product fermentation options."--Pub. desc.
Download or read book Enzymatic Hydrolysis of Cellulose written by Bingham H. Van Dyke and published by . This book was released on 1981 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrolysis of Cellulose written by Ross D. Brown and published by . This book was released on 1979 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Level Investigations and Mathematical Modeling of Cellulase catalyzed Hydrolysis of Cellulose written by Jerome M. Fox and published by . This book was released on 2012 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cellulose-to-glucose conversion costs comprise one of the largest expenses in the production of lignocellulosic biofuels, a renewable alternative to traditional fossil fuels. Efforts to reduce these costs by improving the activity of cellulase enzymes, which act within multi-enzyme mixtures to catalyze the hydrolysis of cellulose, have been hindered by uncertainty surrounding the mechanistic origins of rate-limiting phenomena and by an incomplete understanding of complementary enzyme function. In this work, we employed mechanistic models of enzymatic action alongside experimental studies of enzyme-enzyme synergy to investigate kinetic impediments encountered by cellulase enzymes as they catalyze the hydrolysis of cellulose. Using several mechanistic models of enzymatic hydrolysis, we show how hydrolysis kinetics and optimal cellulolytic mixture compositions are dependent on the nature of the cellulosic substrate (i.e., particle shape, surface area, degree of polymerization) and the conditions under which it is depolymerized (i.e., hydrolysis and fermentation process conditions). By developing a method to estimate catalysis-specific products within multi-enzyme reactions, we show that cellobiohydrolase enzymes, which catalyze processive hydrolysis from cellulose chain ends, encounter rate limitations that result, not from intrinsic kinetics, but from slow rates of chain complexation and from morphological obstacles to processivity. And using photoactivated localization microscopy (PALM) to produce pointillistic maps of carbohydrate-binding modules (CBMs) bound to cotton, we develop an order parameter to quantify the different spatial arrangements of adsorbed CBMs and use that order parameter to explain synergy between cellulase enzymes designed to target different surface structures. The results of this work reveal strategies for using morphological targeting to enhance enzyme-enzyme cooperativity within cellulolytic mixtures, thereby improving their overall activity and lowering the cost of cellulose hydrolysis.
Download or read book Cellulose written by Theo G.M. Van De Ven and published by BoD – Books on Demand. This book was released on 2013-08-28 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cellulose is destined to play a major role in the emerging bioeconomy. Awareness of the environment and a depletion of fossil fuels are some of the driving forces for looking at forest biomaterials for an alternative source of energy, chemicals and materials. The importance of cellulose is widely recognized world-wide and as such the field of cellulose science is expanding exponentially. Cellulose, the most abundant biopolymer on earth, has unique properties which makes it an ideal starting point for transforming it into useful materials. To achieve this, a solid knowledge of cellulose is essential. As such this book on cellulose, the first in a series of three, is very timely. It deals with fundamental aspect of cellulose, giving the reader a good appreciation of the richness of cellulose properties. Book Cellulose - Fundamental Aspects is a good introduction to books Cellulose - Medical, Pharmaceutical and Electronic Applications and Cellulose - Biomass Conversion , in which applications of cellulose and its conversion to other materials are treated.
Download or read book Rate Limitations in Cellulose Hydrolysis Kinetics Arising from the Productive Cellulase Binding Capacity written by Jennifer Nill and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lignocellulosic biomass is the most promising feedstock for sustainable production of renewable biofuels and biochemicals. However, the structural polysaccharides comprising the plant cell wall have evolved to resist enzymatic breakdown, rendering efficient conversion of biomass to soluble sugars elusive at a practical industrial scale. Cellulose, the most abundant biopolymer, is a polymer of glucose linked by [beta]-1,4 glycosidic bonds which may be cleaved by a class of enzymes called cellulases. Linear cellulose polymers bundle to form a highly ordered crystalline microfibril, and these microfibrils further aggregate to form fibrils, excluding water and limiting enzyme access to cellulose chains located on the surface of a fibril. Exo-acting cellulases, which cleave soluble sugars from chain ends in multiple processive events, are the enzymes primarily responsible for cellulose solubilization in most cellulolytic cocktails. Exo-cellulases are multi-modular, containing a cellulose binding module (CBM) linked to a catalytic domain (CD), which binds and hydrolyzes a single cellulose molecule. In order for an exocellulase to hydrolyze cellulose, it must attach to the surface of cellulose and thread a chain end through its catalytic tunnel. Enzymes bound by their catalytic domain and actively producing soluble sugars are termed productively bound, while those that are bound and inactive are considered non-productively bound. We hypothesized that the accessibility of cellulose to productive binding by cellulases is rate limiting in cellulose hydrolysis, and that the total number of sites at which a cellulase can productively bind (the productive binding capacity) evolves throughout hydrolysis and both the magnitude and rate of depletion can be altered by chemical and enzymatic treatments. We utilized bulk biochemical measurements in conjunction with a mechanistic model describing cellulose hydrolysis at the molecular level to gain a multi-scale understanding of cellulose hydrolysis rate limitations. Our mechanistic model incorporates the productive binding capacity of cellulose as a temporally evolving variable in order to capture the substrate evolution that we have shown to occur. We conducted simulations capturing the initial hydrolysis burst phase (
Download or read book Cellulases and Their Applications written by George J. Hajny and published by . This book was released on 1969 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Glucosidases Advances in Research and Application 2013 Edition written by and published by ScholarlyEditions. This book was released on 2013-06-21 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glucosidases—Advances in Research and Application: 2013 Edition is a ScholarlyEditions™ book that delivers timely, authoritative, and comprehensive information about Cellulases. The editors have built Glucosidases—Advances in Research and Application: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Cellulases in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Glucosidases—Advances in Research and Application: 2013 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Adsorption desorption of Cellulases from Cellulose and Their Characterization by HPLC written by Donald Edwin Otter and published by . This book was released on 1987 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamental Study of the Mechanism and Kinetics of Cellulose Hydrolysis by Acids and Enzymes Progress Report June 1 1975 December 31 1975 written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project deals with acidic and enzymatic hydrolysis of cellulosic materials. Highlights of the first eight months of out project are as follows. (1) Essentially homogeneous C1, C3 and Cellobiase enzyme have been isolated from Cellulase-Onozuka of Trichodeima viride origin. Besides the 3 major components, one protein of a molecular weight of 10,000 was purified, which has strong C3 activity and also another (M.W. 23,000) with strong C1 activity. (2) Kinetics of Cellobiase has been investigated and its kinetics constant accurately determined. Immobilization of this enzyme on porous glass was successful. (3) Absorption of SO2 at atmospheric pressure increased digestibility of delignated cellulose but not the natural materials such as corn stalk. A pressurizable absorption unit is being built. (4) Kinetics models for purified C1 and C3 are postulated and equations derived. Experimental tests will be made when sufficient quantities of purified C1 and C3 enzyme are prepared. (5) A lignin digesting, white-rot fungus, Pleurotus ostreatus, has cultivated in our laboratory. It has grown well and heavy. (6) A number of electron micrographs were made with untreated cellulosic materials, which showed that the method of drying the specimens for electromicroscopy is important. Ordinary drying procedures will alter their physical structures. A technique, critical point drying, is being practiced, which will not change the structure. (auth).
Download or read book Computational and Experimental Investigation of the Enzymatic Hydrolysis of Cellulose written by Prabuddha Bansal and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The enzymatic hydrolysis of cellulose to glucose by cellulases is one of the major steps in the conversion of lignocellulosic biomass to biofuel. This hydrolysis by cellulases, a heterogeneous reaction, currently suffers from some major limitations, most importantly a dramatic rate slowdown at high degrees of conversion in the case of crystalline cellulose. Various rate-limiting factors were investigated employing experimental as well as computational studies. Cellulose accessibility and the hydrolysable fraction of accessible substrate (a previously undefined and unreported quantity) were shown to decrease steadily with conversion, while cellulose reactivity, defined in terms of hydrolytic activity per amount of actively adsorbed cellulase, remained constant. Faster restart rates were observed on partially converted cellulose as compared to uninterrupted hydrolysis rates, supporting the presence of an enzyme clogging phenomenon. : Cellulose crystallinity is a major substrate property affecting the rates, but its quantification has suffered from lack of consistency and accuracy. Using multivariate statistical analysis of X-ray data from cellulose, a new method to determine the degree of crystallinity was developed. Cel7A CBD is a promising target for protein engineering as cellulose pretreated with Cel7A CBDs exhibits enhanced hydrolysis rates resulting from a reduction in crystallinity. However, for Cel7A CBD, a high throughput assay is unlikely to be developed. In the absence of a high throughput assay (required for directed evolution) and extensive knowledge of the role of specific protein residues (required for rational protein design), the mutations need to be picked wisely, to avoid the generation of inactive variants. To tackle this issue, a method utilizing the underlying patterns in the sequences of a protein family has been developed.
