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A study of over production and enhanced secretion of enzymes. Quarterly report 1

Description: The current project is concerned with the over-production and enhanced secretion of PPO, cellulase and lignin peroxidase. The project is divided into two segments: over-production of lignocellulolytic enzymes by genetic engineering methodologies and hyper-production and enhanced secretion of these enzymes by biochemical/electron microscopical techniques. The former approach employs recombinant DNA procedures, ligation of appropriate nuclease generated DNA fragments into a vector and the subsequent transformation of Escherichia coli to yield E. coli harboring a C. versicolor DNA insert. The biochemistry/electron microscopical method involves substrate induction and the time-dependent addition of respiration and PPO inhibitors to elevate C.versicolor`s ability to synthesize and secrete lignocellulosic enzymes. In this connection, cell fractionation/kinetic analysis, TEM immunoelectron microscopic localization and TEM substrate localization of PPO are being employed to assess the route of secretion. Both approaches will culminate in the batch culture of either E. coli or C. versicolor, in a fermentor with the subsequent development of rapid isolation and purification procedures to yield elevated quantities of pure lignocellulosic enzymes. During the past year, research effort were directed toward determining the route of polyphenol oxidase (PPO) secretion by the wood-decay fungus, Coriolus versicolor. In addition, research activities were continued to over-produce and to purify PPO as well as define the time-dependent intra- and extra-cellular appearances of C. versicolor ligninases and cellulases.
Date: December 28, 1992
Creator: Dashek, W.V.
Partner: UNT Libraries Government Documents Department

A study of over-production and enhanced secretion of enzymes. Quarterly report 2

Description: This project is concerned with the over-production of ligno-cellulolytic enzymes which are relevant to the paper-pulp industry and agricultural community. Since ligno-cellulosics are components of wood, the project involves the forest, a renewable energy resource. Attention is focused on the following: over-production of polyphenol oxidase; establishment of the route of polyphenol oxidase secretion; regulation of polyphenol oxidase secretion; purification of extracellular oxidase.
Date: April 8, 1993
Creator: Dashek, W.V.
Partner: UNT Libraries Government Documents Department

Ethanol production from dry-mill corn starch in a fluidized-bed bioreactor

Description: The development of a high-rate process for the production of fuel ethanol from dry-mill corn starch using fluidized-bed bioreactor (FBR) technology is discussed. Experiments were conducted in a laboratory scale FBR using immobilized biocatalysts. Two ethanol production process designs were considered in this study. In the first design, simultaneous saccharification and fermentation was performed at 35 C using {kappa}-carageenan beads (1.5 mm to 1.5 mm in diameter) of co-immobilized glucoamylase and Zymomonas mobilis. For dextrin feed concentration of 100 g/L, the single-pass conversion ranged from 54% to 89%. Ethanol concentrations of 23 to 36 g/L were obtained at volumetric productivities of 9 to 15 g/L-h. No accumulation of glucose was observed, indicating that saccharification was the rate-limiting step. In the second design, saccharification and fermentation were carried out sequentially. In the first stage, solutions of 150 to 160 g/L dextrins were pumped through an immobilized glucoamylase packed column maintained at 55 C. Greater than 95% conversion was obtained at a residence time of 1 h, giving a product of 165 to 170 g glucose/L. In the second stage, these glucose solutions were fed to the FBR containing Z. mobilis immobilized in {kappa}-carageenan beads. At a residence time of 2 h, 94% conversion and ethanol concentration of 70 g/L was achieved, giving an overall productivity of 23 g/L-h.
Date: August 1, 1998
Creator: Krishnan, M. S.; Nghiem, N. P. & Davison, B. H.
Partner: UNT Libraries Government Documents Department

Regulation of coal polymer degradation by fungi. Eighth quarterly report, [April--June 1996]

Description: This project addresses the solubilization of low-rank coal (leonardite) by lignin degrading fungi. During this reporting period efforts were focused on determining the effect of pH on coal solubilization by oxalate ion and other biologically important compounds that might function as metal chelators, on the role of laccase in coal solubilization and metabolism, on decolorization of soluble coal macromolecule by Phanerochaete chrysosporium and T. versicolor in solid agar media, and on solubilization of coal in slurry cultures and solid phase reactors.
Date: July 28, 1996
Creator: Irvine, R.L. & Bumpus, J.A.
Partner: UNT Libraries Government Documents Department

Enzymatic degradation of plutonium-contaminated cellulose products

Description: Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated either with crude oil or with radionuclides. This presentation describes the use of one such enzyme preparation (Rapidase{trademark}) for the degradation of cotton sorbents intentionally contaminated with low levels of plutonium. This is part of a feasibility study to determine if such treatments have a role in reducing the volume of low level and transuranic wastes to minimize the amount of radionuclide-contaminated waste that must be disposed of in secured storage areas.
Date: March 1, 1999
Creator: Heintz, C.E.; Rainwater, K.A.; Swift, L.M.; Barnes, D.L.; Worl, L. & Avens, L.
Partner: UNT Libraries Government Documents Department

Preparation for commercial demonstration of biomass-to-ethanol conversion technology. Final report

Description: The objective of this program was to complete the development of a commercially viable process to produce fuel ethanol from renewable cellulosic biomass. The program focused on pretreatment, enzymatic hydrolysis, and fermentation technologies where Amoco has a unique proprietary position. Assured access to low-cost feedstock is a cornerstone of attractive economics for cellulose to ethanol conversion in the 1990s. Most of Amoco`s efforts in converting cellulosic feedstocks to ethanol before 1994 focused on using paper from municipal solid waste as the feed. However, while many municipalities and MSW haulers expressed interest in Amoco`s technology, none were willing to commit funding to process development. In May, 1994 several large agricultural products companies showed interest in Amoco`s technology, particularly for application to corn fiber. Amoco`s initial work with corn fiber was encouraging. The project work plan was designed to provide sufficient data on corn fiber conversion to convince a major agriculture products company to participate in the construction of a commercial demonstration facility.
Date: July 1, 1997
Partner: UNT Libraries Government Documents Department

Seventeenth symposium on biotechnology for fuels and chemicals. Program and abstracts

Description: This volume contains the abstracts of oral and poster presentations made at the Seventeenth Symposium on Biotechnology for Fuels and Chemicals. Session titles include Thermal, Chemical, and Biological Processing; Applied Biological Research; Bioprocessing Research; Special Topics Discussion Groups; Process Economics and Commercialization; and Environmental Biotechnology.
Date: May 1, 1995
Partner: UNT Libraries Government Documents Department

Over production of lignocellulosic enzymes of Coriolus versicolor by genetic engineering methodology. Final report

Description: The project seeks to understand the biological and chemical processes involved in the secretion of the enzyme polyphenol oxidase (PPO) by the hyphae, the basic unit of the filamentous fungus Coriolus versicolor. These studies are made to determine rational strategies for enhanced secretion of PPO, both with the use of recombinant DNA techniques and without. This effort focuses on recombinant DNA techniques to enhance enzyme production. The major thrust of this project was two-fold: to mass produce C. versicolor tyrosinase (polyphenol oxidase) by genetic engineering as well as cultural manipulations; and to utilize PPO as a biocatalyst in the processing of lignocellulose as a renewable energy resource. In this study, the assessment of genomic and cDNA recombinant clones with regards to the overproduction of PPO continued. Further, immunocytochemical techniques were employed to assess the mechanism(s) involved in the secretion of PPO by the hyphae. Also, factors influencing PPO secretion were examined.
Date: July 1, 1998
Creator: Williams, A. L.
Partner: UNT Libraries Government Documents Department

Cyclodextrin-based surface acoustic wave chemical microsensors

Description: Cyclodextrin thin films were fabricated using either self-assembled monolayer (SAM) or solgel techniques. The resulting host receptor thin films on the substrates of surface acoustic wave (SAW) resonators were studied as method of tracking organic toxins in vapor phase. The mass loading of surface-attached host monolayers on SAW resonators gave frequency shifts corresponding to typical monolayer surface coverages for SAM methods and ``multilayer`` coverages for sol-gel techniques. Subsequent exposure of the coated SAW resonators to organic vapors at various concentrations, typically 5,000 parts per millions (ppm) down to 100 parts per billions (ppb) by mole, gave responses indicating middle-ppb-sensitivity ({approximately}50 ppb) for those sensor-host-receptors and organic-toxin pairs with optimum mutual matching of polarity, size, and structural properties.
Date: July 1, 1996
Creator: Li, D.Q.; Shi, J.X.; Springer, K. & Swanson, B.I.
Partner: UNT Libraries Government Documents Department

Enzymes for Degradation of Energetic Materials and Demilitarization of Explosives Stockpiles - SERDP Annual (Interim) Report, 12/98

Description: The current stockpile of energetic materials requiring disposal contains about half a million tons. Through 2001, over 2.1 million tons are expected to pass through the stockpile for disposal. Safe and environmentally acceptable methods for disposing of these materials are needed. This project is developing safe, economical, and environmentally sound processes using biocatalyst (enzymes) to degrade energetic materials and to convert them into economically valuable products. Alternative methods for destroying these materials are hazardous, environmentally unacceptable, and expensive. These methods include burning, detonation, land and sea burial, treatment at high temperature and pressure, and treatment with harsh chemicals. Enzyme treatment operates at room temperature and atmospheric pressure in a water solution.
Date: January 18, 1999
Creator: Shah, M.M.
Partner: UNT Libraries Government Documents Department

Enzymatic degradation of plutonium-contaminated cellulose products

Description: Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown previously that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated either with crude oil or with uranium. This presentation describes the use of one such enzyme preparation (Rapidase{trademark}, manufactured by Genencor, Rochester, NY) for the degradation of cotton sorbents intentionally contaminated with low levels of plutonium. This is part of a feasibility study to determine if such treatments have a role in reducing the volume of low level and transuranic wastes to minimize the amount of radionuclide-contaminated waste destined for costly disposal options.
Date: June 1, 1999
Creator: Heintz, C.E.; Rainwater, K.A.; Swift, L.M.; Barnes, D.L. & Worl, L.A.
Partner: UNT Libraries Government Documents Department

Identification of the primary mechanism for fungal lignin degradation. Progress report

Description: Many lignin-degrading fungi appear to lack lignin peroxidase (LiP), an enzyme generally thought important for fungal ligninolysis. The authors are working with one of these fungi, Ceriporiopsis subvermispora, an aggressive white-rotter that selectively removes lignin from wood. During this project period, they have obtained the following principal results: new polymeric lignin model compounds were developed to assist in the elucidation of fungal ligninolytic mechanisms; experiments with one of the polymeric lignin models showed that C. subvermispora cultures which express no detectable LiP activity are nevertheless able to degrade nonphenolic lignin structures, this result is significant because LiPs were previously considered essential for fungal attack on these recalcitrant structures, which constitute about 90% of lignin; manganese peroxidases (MnPs), which C. subvermispora does produce, catalyze the peroxidation of unsaturated fatty acids to give fatty acid hydroperoxides, fatty acid hydroperoxides are also used by MnP as oxidants (in place of H{sub 2}O{sub 2}) that support the MnP catalytic cycle, these results indicate that MnP turnover in the presence of unsaturated lipids generates reactive lipid oxyradicals that could act as oxidant of other molecules; MnP-mediated lipid peroxidation results in the co-oxidative cleavage of nonphenolic lignin structures, the MnP/lipid peroxidation system may therefore provide C. subvermispora and other LiP-negative fungi with a mechanism to degrade the principal structures of lignin.
Date: June 1, 1997
Partner: UNT Libraries Government Documents Department

Carbonic Acid Pretreatment of Biomass

Description: This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic acid compared to ...
Date: May 31, 2003
Creator: Walsum, G. Peter van; Jayawardhana, Kemantha; Yourchisin, Damon; McWilliams, Robert & Castleberry, Vanessa
Partner: UNT Libraries Government Documents Department

Regulation of coal polymer degradation by fungi. Eighth quarterly report, [January--March 1996]

Description: Progress is reported on solubilization of low-rank coal by enzyme activity derived from Trametes versicolor or P. chrysosporium. Specifically during the reporting period efforts were directed towards the determining the effect of pH on solubilization of leonardite, the role of laccase in low coal solubilization and metabolism, the decolorization of soluble coal macromolecule by P. chrysosprium and T. versicolor in solid agar gel, and the solubilization of low rank coal in slurry cultures and solid phase reactors.
Date: July 28, 1996
Creator: Irvine, R.L. & Bumpus, J.A.
Partner: UNT Libraries Government Documents Department

Optimizing cellulase mixtures for maximum rate and extent of hydrolysis. Final report

Description: Pure Thomomonospora fusca and Trichoderma reesei cellulases and their mixtures were studied to determine the optimal set of cellulases for biomass hydrolysis. The objective was to reduce the cost of cellulase in order to help lower the overall processing cost of the enzymatic conversion of biomass cellulose to sugars, which can then be fermented into fuels and other energy-intensive chemicals. No cellulase mixture was obtained that was much better than the best commercially available preparations. However, the study has greatly increased knowledge of T. fusca cellulases, synergism, and cellulose binding, and provide evidence that future work will produce cellulases with higher activity in degrading crystalline cellulose. T. fusca cellulases may have good industrial potential because: (1) they are compatible with industrial processes that operate at elevated temperatures; (2) they retain 90% of their activity under neutral or basic conditions, which provides a great deal of flexibility in reactor design and operation; and (3) tools are now available to change specific amino acid residues in their catalytic domains and to assess how these changes influence catalysis. 74 refs.
Date: March 1, 1997
Creator: Walker, L.P. & Wilson, D.B.
Partner: UNT Libraries Government Documents Department

The study of redox-active inorganic substituents of cellulase enzymes. Quarterly report, August 25--November 25, 1993

Description: Attention is focused on the following: modification of CBHI with bis (2,2-bipyridine) ruthenium (II); and cellulase activity assay. CBHI was reacted with Ru(bpy) 2 (H{sub 2}O){sup 2+} at room temperature in 100 mM HEPES buffer (pH7.0) for 2 and 4 hours. The reaction vial was covered with aluminum foil to shield off light. Purified CBHI at a concentration of 1.5 mg/ml was generally employed, and a 10-fold excess ruthenium reagent was used. The reaction was quenched by diluting the reaction mixture with 50 mM acetate buffer (pH 5.0) and separating the excess Ru reagent using Amicon stirred filtration (yM-10) at 4 C. In parallel experiments the buffer was replaced with imidazole buffer 100 mM, pH 7.0, in order to block the axial ligand on the Ru(bpy)2 histidine. In a final exchange all buffers were replaced with acetate buffer in which the cellulase activity assay was carried out. UV/vis absorption spectra of native and modified CBHI were taken and compared.
Date: December 31, 1993
Partner: UNT Libraries Government Documents Department

Bioremediation of uranium contaminated soils and wastes

Description: Contamination of soils, water, and sediments by radionuclides and toxic metals from uranium mill tailings, nuclear fuel manufacturing and nuclear weapons production is a major concern. Studies of the mechanisms of biotransformation of uranium and toxic metals under various microbial process conditions has resulted in the development of two treatment processes: (1) stabilization of uranium and toxic metals with reduction in waste volume and (2) removal and recovery of uranium and toxic metals from wastes and contaminated soils. Stabilization of uranium and toxic metals in wastes is accomplished by exploiting the unique metabolic capabilities of the anaerobic bacterium, Clostridium sp. The radionuclides and toxic metals are solubilized by the bacteria directly by enzymatic reductive dissolution, or indirectly due to the production of organic acid metabolites. The radionuclides and toxic metals released into solution are immobilized by enzymatic reductive precipitation, biosorption and redistribution with stable mineral phases in the waste. Non-hazardous bulk components of the waste volume. In the second process uranium and toxic metals are removed from wastes or contaminated soils by extracting with the complexing agent citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, followed by photochemical degradation of the uranium citrate complex which is recalcitrant to biodegradation. The toxic metals and uranium are recovered in separate fractions for recycling or for disposal. The use of combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in clean-up and disposal costs.
Date: December 31, 1998
Creator: Francis, A.J.
Partner: UNT Libraries Government Documents Department

Production of ethanol from starch by co-immobilized Zymomonas mobilis -- Glucoamylase in a fluidized-bed reactor

Description: The production of ethanol from starch was studied in a fluidized-bed reactor (FBR) using co-immobilized Zymomonas mobilis and glucoamylase. The FBR was a glass column of 2.54 cm in diameter and 120 cm in length. The Z. mobilis and glucoamylase were co-immobilized within small uniform beads (1.2 to 2.5 mm diameter) of {kappa}-carrageenan. The substrate for ethanol production was a soluble starch. Light steep water was used as the complex nutrient source. The experiments were performed at 35 C and pH range 4.0 to 5.5. The substrate concentrations ranged from 40 to 185 g/L and the feed rates from 10 to 37 mL/min. Under relaxed sterility conditions, the FBR was successfully operated for a period of 22 days, during which no contamination or structural failure of the biocatalyst beads was observed. Maximum volumetric productivity of 38 g ethanol/L-h, which was 76% of the theoretical value, was obtained. Typical ethanol volumetric productivity was in the range of 15 to 20 g/L-h. The average yield was 0.51 g ethanol/g substrate consumed, which was 90% of the theoretical yield. Very low levels of glucose were observed in the reactor, indicating that starch hydrolysis was the rate-limiting step.
Date: August 1, 1997
Creator: Sun, M.Y.; Davison, B.H.; Bienkowski, P.R.; Nghiem, N.P. & Webb, O.
Partner: UNT Libraries Government Documents Department

Commercialization of the Conversion of Bagasse to Ethanol. Summary quarterly report for the period January-September 1999

Description: These studies were intended to further refine sugar yield parameters which effect sugar yield such as feedstock particle size, debris, acid soak time, temperature, dewatering, and pretreatment conditions (such as temperature, reaction time, percentage solids concentration, acid concentration), liquid-solids separation, and detoxification parameters (such as time temperature and mixing of detoxification ingredients). Validate and refine parameters, which affect ethanol yield such as detoxification conditions mentioned above, and to fermenter conditions such as temperature, pH adjustment, aeration, nutrients, and charging sequence. Materials of construction will be evaluated also. Evaluate stillage to determine clarification process and suitability for recycle; evaluate lignocellulosic cake for thermal energy recovery to produce heat and electricity for the process; and Support Studies at UF - Toxin Amelioration and Fermentation; TVA work will provide pre-hydroylsates for the evaluation of BCI proprietary methods of toxin amelioration. Pre-hydrolysates from batch studies will allow the determination of the range of allowable hydrolyze conditions that can be used to produce a fermentable sugar stream. This information is essential to guide selection of process parameters for refinement and validation in the continuous pretreatment reactor, and for overall process design. Additional work will be conducted at UFRFI to develop improved strains that are resistant to inhibitors. The authors are quite optimistic about the long-term prospects for this advancement having recently developed strains with a 25%--50% increase in ethanol production. The biocatalyst platform selected originally, genetically engineered Escherichia coli B, has proven to be quite robust and adaptable.
Date: February 1, 2000
Partner: UNT Libraries Government Documents Department

Biomimetic methane oxidation. Final report, October 1, 1989--June 1, 1995

Description: Transportation fuels are a critical energy commodity and they impact nearly every sector of this country. The need for transportation fuels is projected well into the next century. Consequently, there is a strong emphasis on the economical conversion of other domestic fossil energy resources to liquid hydrocarbons that can be used as transportation fuels. Natural gas is currently a readily available resource that has a positive future outlook considering its known and anticipated reserves. There is intense government and industrial interest in developing economic technologies to convert natural gas to liquid fuels. Methane, CH{sub 4}, is the primary hydrocarbon (85-95%) in natural gas. This document covers the following: production soluable of methane monooxygenase; production of particulate methane monooxygenase; production of methane monooxygenase in continuous culture; subunit resolution for active site identification of methylosinus trichosporium OB3b soluble methane monooxygenase; the synthesis and characterization of new copper coordination complexes contairing the asymmetric coordinating chelate ligand application to enzyme active site modeling; the synthesis and characterization of new iron coordination complexes utilizing an asymmetric coordinating chelate ligand; further characterization of new bionuclear iron complexes.
Date: July 1, 1995
Creator: Watkins, B.E.; Satcher, J.H. Jr.; Droege, M.W. & Taylor, R.T.
Partner: UNT Libraries Government Documents Department

Carbonic Acid Retreatment of Biomass

Description: This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic acid ...
Date: June 1, 2003
Creator: university, Baylor
Partner: UNT Libraries Government Documents Department

FRACTIONATION OF LIGNOCELLULOSIC BIOMASS FOR FUEL-GRADE ETHANOL PRODUCTION

Description: PureVision Technology, Inc. (PureVision) of Fort Lupton, Colorado is developing a process for the conversion of lignocellulosic biomass into fuel-grade ethanol and specialty chemicals in order to enhance national energy security, rural economies, and environmental quality. Lignocellulosic-containing plants are those types of biomass that include wood, agricultural residues, and paper wastes. Lignocellulose is composed of the biopolymers cellulose, hemicellulose, and lignin. Cellulose, a polymer of glucose, is the component in lignocellulose that has potential for the production of fuel-grade ethanol by direct fermentation of the glucose. However, enzymatic hydrolysis of lignocellulose and raw cellulose into glucose is hindered by the presence of lignin. The cellulase enzyme, which hydrolyzes cellulose to glucose, becomes irreversibly bound to lignin. This requires using the enzyme in reagent quantities rather than in catalytic concentration. The extensive use of this enzyme is expensive and adversely affects the economics of ethanol production. PureVision has approached this problem by developing a biomass fractionator to pretreat the lignocellulose to yield a highly pure cellulose fraction. The biomass fractionator is based on sequentially treating the biomass with hot water, hot alkaline solutions, and polishing the cellulose fraction with a wet alkaline oxidation step. In September 2001 PureVision and Western Research Institute (WRI) initiated a jointly sponsored research project with the U.S. Department of Energy (DOE) to evaluate their pretreatment technology, develop an understanding of the chemistry, and provide the data required to design and fabricate a one- to two-ton/day pilot-scale unit. The efforts during the first year of this program completed the design, fabrication, and shakedown of a bench-scale reactor system and evaluated the fractionation of corn stover. The results from the evaluation of corn stover have shown that water hydrolysis prior to alkaline hydrolysis may be beneficial in removing hemicellulose and lignin from the feedstock. In addition, alkaline hydrolysis ...
Date: October 1, 2002
Creator: Guffey, F.D. & Wingerson, R.C.
Partner: UNT Libraries Government Documents Department