Download or read book Fundamental Study on Kinetics and Transport Phenomena in Low Water Dilute Acid Total Hydrolysis of Cellulosic Biomass written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this research is to delineate the process of the dilute-acid hydrolysis of biomass and seek better understanding of the reactions involving dilute-acid treatment of lignocellulosic biomass. Specifically the scope of the work entails the following two primary technical elements: Verification of the heterogeneous nature of the reaction mechanism in dilute-acid hydrolysis of cellulosic component of the biomass. Experimental investigation to identify the overall reaction pattern and the kinetic constants associated with dilute-acid hydrolysis of the cellulosic component of the agricultural residues.

Download or read book Fermentation and Biochemical Engineering Handbook written by Celeste M. Todaro and published by William Andrew. This book was released on 2014-03-27 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete reference for fermentation engineers engaged in commercial chemical and pharmaceutical production, Fermentation and Biochemical Engineering Handbook emphasizes the operation, development and design of manufacturing processes that use fermentation, separation and purification techniques. Contributing authors from companies such as Merck, Eli Lilly, Amgen and Bristol-Myers Squibb highlight the practical aspects of the processes—data collection, scale-up parameters, equipment selection, troubleshooting, and more. They also provide relevant perspectives for the different industry sectors utilizing fermentation techniques, including chemical, pharmaceutical, food, and biofuels. New material in the third edition covers topics relevant to modern recombinant cell fermentation, mammalian cell culture, and biorefinery, ensuring that the book will remain applicable around the globe. It uniquely demonstrates the relationships between the synthetic processes for small molecules such as active ingredients, drugs and chemicals, and the biotechnology of protein, vaccine, hormone, and antibiotic production. This major revision also includes new material on membrane pervaporation technologies for biofuels and nanofiltration, and recent developments in instrumentation such as optical-based dissolved oxygen probes, capacitance-based culture viability probes, and in situ real-time fermentation monitoring with wireless technology. It addresses topical environmental considerations, including the use of new (bio)technologies to treat and utilize waste streams and produce renewable energy from wastewaters. Options for bioremediation are also explained. - Fully updated to cover the latest advances in recombinant cell fermentation, mammalian cell culture and biorefinery, along with developments in instrumentation - Industrial contributors from leading global companies, including Merck, Eli Lilly, Amgen, and Bristol-Myers Squibb - Covers synthetic processes for both small and large molecules

Download or read book Kinetic Characterization of Hot Water and Dilute Acid Pretreatment of Lignocellulosic Biomass written by Lishi Yan and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A kinetic model was developed to depict the biomass degradation in flowthrough system. This model predicted the sugar generation more precisely than the conventional homogeneous first-order reaction models. Mass transfer limitations were minimized using 4mm biomass particle sizes with 4g biomass loading at 25mL/min flow rate, produced hydrolyzate slurries with 13g/L potential sugar concentrations.

Download or read book The Mild Hydrolysis of Cellulose written by Warren Froemming Busse and published by . This book was released on 1924 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Kinetic and Modeling Investigation to Provide Design Guidelines for the NREL Dilute acid Process Aimed at Total Hydrolysis fractionation of Lignocellulosic Biomass written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Following up on previous work, subcontractor investigated three aspects of using NREL ''pretreatment'' technology for total hydrolysis (cellulose as well as hemicellulose) of biomass. Whereas historic hydrolysis of biomass used either dilute acid or concentrated acid technology for hydrolysis of both hemicellulose and cellulose, NREL has been pursuing very dilute acid hydrolysis of hemicellulose followed by enzymatic hydrolysis of cellulose. NREL's countercurrent shrinking-bed reactor design for hemicellulose hydrolysis (pretreatment) has, however, shown promise for total hydrolysis. For the first task, subcontractor developed a mathematical model of the countercurrent shrinking bed reactor operation and, using yellow poplar sawdust as a feedstock, analyzed the effect of: initial solid feeding rate, temperature, acid concentration, acid flow rate, Peclet number (a measure of backmixing in liquid flow), and bed shrinking. For the second task, subcontractor used laboratory trials, with yellow poplar sawdust and 0.07 wt% sulfuric acid at various temperatures, to verify the hydrolysis of cellulose to glucose (desired) and decomposition of glucose (undesired) and determine appropriate parameters for use in kinetic models. Unlike cellulose and hemicellulose, lignins, the third major component of biomass, are not carbohydrates that can be broken down into component sugars. They are, however, aromatic complex amorphous phenolic polymers that can likely be converted into low-molecular weight compounds suitable for production of fuels and chemicals. Oxidative degradation is one pathway for such conversion and hydrogen peroxide would be an attractive reagent for this, as it would leave no residuals. For the third task, subcontractor reacted lignin with hydrogen peroxide under various conditions and analyzed the resulting product mix.

Download or read book Mechanism of Depolymerization of Cellulose in Low Sulfuric Acid Medium Kinetic Investigation and Stochastic Simulation written by Zin Eddine Dadach and published by GRIN Verlag. This book was released on 2018-02-02 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral Thesis / Dissertation from the year 1994 in the subject Engineering - Chemical Engineering, grade: 3.7, Université Laval, language: English, abstract: The final objective of this investigation is to model the kinetic behaviour of cellulose during hydrolysis by means of stochastic simulation. Part I of this study will thus report the experimental determination of kinetic parameters to be used in the simulation. These were established from kinetic experiments on cellobiose hydrolysis and glucose degradation. Furthermore, both cotton morphology and outer layer are analysed and the effects of cotton wax on cellulose depolymerization are studied. Finally, the effects of cotton milling on both cellulose depolymerization and glucose yield are investigated and presented in this first part. Part II will deal more specifically with the stochastic modelling of these data. This simulation should be realistic enough to allow a representation of the effect of milling on the cellulose structure and its influence on acid hydrolysis kinetics.

Download or read book Fundamental Study of Structural Features Affecting Enzymatic Hydrolysis of Lignocellulosic Biomass written by Li Zhu and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lignocellulose is a promising and valuable alternative energy source. Native lignocellulosic biomass has limited accessibility to cellulase enzyme due to structural features; therefore, pretreatment is an essential prerequisite to make biomass accessible and reactive by altering its structural features. The effects of substrate concentration, addition of cellobiase, enzyme loading, and structural features on biomass digestibility were explored. The addition of supplemental cellobiase to the enzyme complex greatly increased the initial rate and ultimate extent of biomass hydrolysis by converting the strong inhibitor, cellobiose, to glucose. A low substrate concentration (10 g/L) was employed to prevent end-product inhibition by cellobiose and glucose. The rate and extent of biomass hydrolysis significantly depend on enzyme loading and structural features resulting from pretreatment, thus the hydrolysis and pretreatment processes are intimately coupled because of structural features. Model lignocelluloses with various structural features were hydrolyzed with a variety of cellulase loadings for 1, 6, and 72 h. Glucan, xylan, and total sugar conversions at 1, 6, and 72 h were linearly proportional to the logarithm of cellulase loadings from approximately 10% to 90% conversion, indicating that the simplified HCH-1 model is valid for predicting lignocellulose digestibility. Carbohydrate conversions at a given time versus the natural logarithm of cellulase loadings were plotted to obtain the slopes and intercepts which were correlated to structural features (lignin content, acetyl content, cellulose crystallinity, and carbohydrate content) by both parametric and nonparametric regression models. The predictive ability of the models was evaluated by a variety of biomass (corn stover, bagasse, and rice straw) treated with lime, dilute acid, ammonia fiber explosion (AFEX), and aqueous ammonia. The measured slopes, intercepts, and carbohydrate conversions at 1, 6, and 72 h were compared to the values predicted by the parametric and nonparametric models. The smaller mean square error (MSE) in the parametric models indicates more satisfactorily predictive ability than the nonparametric models. The agreement between the measured and predicted values shows that lignin content, acetyl content, and cellulose crystallinity are key factors that determine biomass digestibility, and that biomass digestibility can be predicted over a wide range of cellulase loadings using the simplified HCH-1 model.

Download or read book Kinetic and Modeling Investigation to Provide Design Guidelines for the NREL Dilute Acid Process Aimed at Total Hydrolysis written by and published by . This book was released on 2004 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following up on previous work, subcontractor investigated three aspects of using NREL ''pretreatment'' technology for total hydrolysis (cellulose as well as hemicellulose) of biomass. Whereas historic hydrolysis of biomass used either dilute acid or concentrated acid technology for hydrolysis of both hemicellulose and cellulose, NREL has been pursuing very dilute acid hydrolysis of hemicellulose followed by enzymatic hydrolysis of cellulose. NREL's countercurrent shrinking-bed reactor design for hemicellulose hydrolysis (pretreatment) has, however, shown promise for total hydrolysis. For the first task, subcontractor developed a mathematical model of the countercurrent shrinking bed reactor operation and, using yellow poplar sawdust as a feedstock, analyzed the effect of: initial solid feeding rate, temperature, acid concentration, acid flow rate, Peclet number (a measure of backmixing in liquid flow), and bed shrinking. For the second task, subcontractor used laboratory trials, with yellow poplar sawdust and 0.07 wt% sulfuric acid at various temperatures, to verify the hydrolysis of cellulose to glucose (desired) and decomposition of glucose (undesired) and determine appropriate parameters for use in kinetic models. Unlike cellulose and hemicellulose, lignins, the third major component of biomass, are not carbohydrates that can be broken down into component sugars. They are, however, aromatic complex amorphous phenolic polymers that can likely be converted into low-molecular weight compounds suitable for production of fuels and chemicals. Oxidative degradation is one pathway for such conversion and hydrogen peroxide would be an attractive reagent for this, as it would leave no residuals. For the third task, subcontractor reacted lignin with hydrogen peroxide under various conditions and analyzed the resulting product mix.

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 Latinsk universitetsprogram ved Magdal Schoenbach Theod Lentes Hustrus d d Kbh d 18 Apr 1670 written by and published by . This book was released on 1670 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamental Studies on the Enzymatic Liquefaction and Rheology of Cellulosic Biomass Via Magnetic Resonance Imaging Velocimetry written by Maria Jose Cardona and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Worldwide need for alternatives to fossil fuels has driven significant research effort toward the development and scale-up of sustainable forms of energy. Second-generation biofuels, obtained from the breakdown of lignocellulosic biomass (e.g., agricultural residues), present a promising alternative. In biofuel production, the enzymatic hydrolysis of cellulose to glucose is currently one of the most expensive steps in the biochemical breakdown of lignocellulosic biomass. Economic considerations for large-scale implementation of this process demand operation at high solids loadings of biomass (>15\% (w/w)) due to potential for higher product concentrations and reduction of water usage throughout the biorefining process. In the high-solids regime, however, biomass slurries form a high viscosity, non-Newtonian slurry that introduces processing challenges, especially during the initial stages of hydrolysis (liquefaction), due to the low availability of water in the bulk phase. Furthermore, a concomitant reduction in glucose yields with increase in solids loadings has been observed, a phenomenon that is not well understood, but if overcome could hold the key to achieving desirable yields during hydrolysis. In order to better understand liquefaction, a magnetic resonance imaging (MRI) rheometer was used to perform in-line, in situ, real-time, and noninvasive studies on biomass slurries undergoing enzymatic hydrolysis. Batch and fed-batch experiments were done on lignocellulosic and cellulosic substrates with both purified and mixtures of enzymes, under various reaction conditions. The mechanism of liquefaction was found to be decoupled from the mechanism of saccharification. In addition, end product inhibition was found to have an impact on both saccharification and liquefaction during the initial stage of hydrolysis, which has an impact on scale-up of hydrolysis processes. Lastly, to address and overcome high-solids limitations, a fed-batch liquefaction process based on using real-time slurry yield stress as a process control variable was designed and tested with a delignified cellulosic substrate. The timing of enzyme addition relative to biomass addition influenced process efficiency, and the upper limit of solids loading was ultimately limited by end product inhibition. The impact of these findings on process kinetic modeling and scale-up are also discussed.

Download or read book Investigating Mass Transport Limitations on Xylan Hydrolysis During Dilute Acid Pretreatment of Poplar written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass transport limitations could be an impediment to achieving high sugar yields during biomass pretreatment and thus be a critical factor in the economics of biofuels production. The objective of this work was to study the mass transfer restrictions imposed by the structure of biomass on the hydrolysis of xylan during dilute acid pretreatment of biomass. Mass transfer effects were studied by pretreating poplar wood at particle sizes ranging from 10 micrometers to 10 mm. This work showed a significant reduction in the rate of xylan hydrolysis in poplar when compared to the intrinsic rate of hydrolysis for isolated xylan that is possible in the absence of mass transfer. In poplar samples we observed no significant difference in the rates of xylan hydrolysis over more than two orders of magnitude in particle size. It appears that no additional mass transport restrictions are introduced by increasing particle size from 10 micrometers to 10 mm. This work suggests that the rates of xylan hydrolysis in biomass particles are limited primarily by the diffusion of hydrolysis products out of plant cell walls. A mathematical description is presented to describe the kinetics of xylan hydrolysis that includes transport of the hydrolysis products through biomass into the bulk solution. The modeling results show that the effective diffusion coefficient of the hydrolysis products in the cell wall is several orders of magnitude smaller than typical values in other applications signifying the role of plant cell walls in offering resistance to diffusion of the hydrolysis products.

Download or read book Fundamental Study of the Mechanism and Kinetics of Cellulose Hydrolysis by Acids and Enzymes Final Report June 1 1978 January 31 1981 written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There are three basic enzymes (e.g., endoglucanase (C3, exoglucanase (C1) and cellobiase) comprising the majority of extracellular cellulase enzymes produced by the cellulolytic mycelial fungi, Trichoderma reesei, and other cellulolytic microorganisms. The enzymes exhibited different mode of actions in respect to the hydrolysis of cellulose and cellulose derived oligosaccharides. In combination, these enzymes complimented each other to hydrolyze cellulose to its basic constituent, glucose. The kinetics of cellobiase were developed on the basis of applying the pseudo-steady state assumption to hydrolyze cellobiose to glucose. The results indicated that cellobiase was subjected to end-product inhibition by glucose. The kinetic modeling of exoglucanase (C1) with respect to cellodextrins was studied. Both glucose and cellobiose were found to be inhibitors of this enzyme with cellobiose being a stronger inhibitor than glucose. Similarly, endoglucanase (C3 is subject to end-product inhibition by glucose. Crystallinity of the cellulose affects the rate of hydrolysis by cellulases. Hence, the changes in crystallinity of cellulose in relation to chemical pretreatment and enzyme hydrolysis was compared. The study of cellulase biosynthesis resulted in the conclusion that exo- and endo-glucanases are co-induced while cellobiase is synthesized independent of the other two enzymes. The multiplicity of cellulase enzymes are the end results of post-translational modification during and/or after the secretion of enzymes into growth environment.

Download or read book Kinetics of Glucose Decomposition During Dilute Acid Hydrolysis of Lignocellulosic Biomass written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physiochemical Characterization of Lignocellulosic Biomass Dissolution by Flowthrough Pretreatment written by and published by . This book was released on 2015 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, comprehensive understanding of biomass solubilization chemistry in aqueous pretreatment such as water-only and dilute acid flowthrough pretreatment is of fundamental importance to achieve the goal of valorizing biomass to fermentable sugars and lignin for biofuels production. In this study, poplar wood was flowthrough pretreated by water-only or 0.05% (w/w) sulfuric acid at different temperatures (220-270 °C), flow rate (25 mL/min), and reaction times (8-90 min), resulting in significant disruption of the lignocellulosic biomass. Ion chromatography (IC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, and solid state cross-polarization/magic angle spinning (CP/MAS) 13C nuclear magnetic resonance (NMR) spectroscopy were applied to characterize the pretreated biomass whole slurries in order to reveal depolymerization as well as solubilization mechanism and identify unique dissolution structural features during these pretreatments. Results showed temperature-dependent cellulose decrystallization in flowthrough pretreatment. Crystalline cellulose was completely disrupted, and mostly converted to amorphous cellulose and oligomers by water-only operation at 270 °C for 10 min and by 0.05 wt % H2SO4 flowthrough pretreatment at 220 °C for 12 min. Flowthrough pretreatment with 0.05% (w/w) H2SO4 led to a greater disruption of structures in pretreated poplar at a lower temperature compared to water-only pretreatment.

Download or read book Dilute acid Hydrolysis of Cellulosic Materials written by and published by . This book was released on 1977 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transport Phenomena in Aqueous Solutions written by Tibor Erdey-Grúz and published by . This book was released on 1974 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: