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John N Saddler - One of the best experts on this subject based on the ideXlab platform.
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the effect of varying Organosolv pretreatment chemicals on the physicochemical properties and cellulolytic hydrolysis of mountain pine beetle killed lodgepole pine
Applied Biochemistry and Biotechnology, 2010Co-Authors: Luis F Del Rio, Richard P Chandra, John N SaddlerAbstract:Mountain pine beetle-killed lodgepole pine (Pinus contorta) chips were pretreated using the Organosolv Process, and their ease of subsequent enzymatic hydrolysis was assessed. The effect of varying pretreatment chemicals and solvents on the substrate’s physicochemical characteristics was also investigated. The chemicals employed were MgCl2, H2SO4, SO2, and NaOH, and the solvents were ethanol and butanol. It was apparent that the different pretreatments resulted in variations in both the chemical composition of the solid and liquid fractions as well in the extent of cellulolytic hydrolysis (ranging from 21% to 82% hydrolysis after 12 h). Pretreatment under acidic conditions resulted in substrates that were readily hydrolyzed despite the apparent contradiction that pretreatment under alkaline conditions resulted in increased delignification (approximately 7% and 10% residual lignin for alkaline conditions versus 17% to 19% for acidic conditions). Acidic pretreatments also resulted in lower cellulose degree of polymerization, shorter fiber lengths, and increased substrate porosity. The substrates generated when butanol/water mixtures were used as the pretreatment solvent were also hydrolyzed more readily than those generated with ethanol/water. This was likely due to the limited miscibility of the solvents resulting in an increased concentration of pretreatment chemicals in the aqueous layer and thus a higher pretreatment severity.
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the potential of enzyme recycling during the hydrolysis of a mixed softwood feedstock
Bioresource Technology, 2009Co-Authors: Xiao Zhang, Mike Paice, Paul Macfarlane, John N SaddlerAbstract:Abstract Despite recent improvement in cellulase enzymes properties, the high cost associated with the hydrolysis step remains a major impediment to the commercialization of full-scale lignocellulose-to-ethanol bioconversion Process. As part of a research effort to develop a commercial Process for bioconversion of softwood residues, we have examined the potential for recycling enzymes during the hydrolysis of mixed softwood substrate pretreated by Organosolv Process. We have used response surface methodology to determine the optimal temperature, pH, ionic strength, and surfactant (Tween 80) concentration for maximizing the recovery of bound protein and enzyme activity from the residual substrates after hydrolysis. Data analysis showed that the temperature, pH and surfactant concentration were the major factors governing enzyme desorption from residual substrate. The optimized conditions were temperature 44.4 °C, pH 5.3 and 0.5% Tween 80. The optimal conditions significantly increased the hydrolysis yield by 25% after three rounds of hydrolysis. This bound enzyme desorption combining with free enzyme re-adsorption is a potential method to recover cellulase enzymes and reduce the cost of enzymatic hydrolysis.
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the bioconversion of mountain pine beetle killed lodgepole pine to fuel ethanol using the Organosolv Process
Biotechnology and Bioengineering, 2008Co-Authors: Richard Yu, John N SaddlerAbstract:Lodgepole pine (Pinus contorta) killed by mountain pine beetle (Dendroctonus ponderosae) (BLP) was compared with healthy lodgepole pine (HLP) for bioconversion to ethanol and high-value co-products. The BLP and HLP chips were pretreated using an ethanol Organosolv Process at a variety of severities. It was shown that the BLP was easier to pretreat and delignify than were the HLP chips. The resulting pretreated BLP substrate had a lower residual lignin, lower degree of polymerization of cellulose, lower cellulose crystallinity, smaller fiber size and thereby a better enzymatic hydrolysability than did the HLP substrates. However, under the same conditions, the BLP showed lower substrate yield and cellulose recovery than did the HLP, which likely resulted from the excessive hydrolysis and subsequent decomposition of the cellulose and hemicellulose during the pretreatment. The BLP wood yielded more ethanol Organosolv lignin than was obtained with the HLP material. The HLP lignin had a lower molecular weight and narrower distribution than did the BLP lignin. It appears that the beetle killed LP is more receptive to Organosolv pretreatment other than a slightly lower recovery of carbohydrates. Biotechnol. Biotechnol. Bioeng. 2008;101: 39–48. © 2008 Wiley Periodicals, Inc.
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the bioconversion of mountain pine beetle killed lodgepole pine to fuel ethanol using the Organosolv Process
Biotechnology and Bioengineering, 2008Co-Authors: Xuejun Pan, Dan Xie, John N SaddlerAbstract:Lodgepole pine (Pinus contorta) killed by mountain pine beetle (Dendroctonus ponderosae) (BLP) was compared with healthy lodgepole pine (HLP) for bioconversion to ethanol and high-value co-products. The BLP and HLP chips were pretreated using an ethanol Organosolv Process at a variety of severities. It was shown that the BLP was easier to pretreat and delignify than were the HLP chips. The resulting pretreated BLP substrate had a lower residual lignin, lower degree of polymerization of cellulose, lower cellulose crystallinity, smaller fiber size and thereby a better enzymatic hydrolysability than did the HLP substrates. However, under the same conditions, the BLP showed lower substrate yield and cellulose recovery than did the HLP, which likely resulted from the excessive hydrolysis and subsequent decomposition of the cellulose and hemicellulose during the pretreatment. The BLP wood yielded more ethanol Organosolv lignin than was obtained with the HLP material. The HLP lignin had a lower molecular weight and narrower distribution than did the BLP lignin. It appears that the beetle killed LP is more receptive to Organosolv pretreatment other than a slightly lower recovery of carbohydrates.
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pretreatment of lodgepole pine killed by mountain pine beetle using the ethanol Organosolv Process fractionation and Process optimization
Industrial & Engineering Chemistry Research, 2007Co-Authors: Xuejun Pan, Dan Xie, Dexter Lam, John N SaddlerAbstract:Lodgepole pine (Pinus contorta) killed by mountain pine beetle (Dendroctonus ponderosae) (MPB-LPP) was evaluated for bioconversion to ethanol using the ethanol Organosolv Process. The pretreatment was optimized using an experimental matrix designed with response surface methodology. It was found that MPB-LPP was easy to pretreat and delignify, but gave low yields of substrate and carbohydrate as a result of excessive hydrolysis and subsequent decomposition of cellulose and hemicellulose during the pretreatment. The center-point conditions (170 °C, 60 min, 1.1% H2SO4 and 65% ethanol) were close to the optimum for the recovery of glucose and ethanol Organosolv lignin. At the center-point conditions, ∼75% of the cellulose present in the untreated wood was recovered in the substrate fraction, and approximately 79% of the lignin in the wood was recovered as ethanol Organosolv lignin (EOL). The combined recovery of carbohydrate in the substrate and water-soluble fractions was ∼83% glucose, ∼46% mannose, ∼53% xy...
Xuejun Pan - One of the best experts on this subject based on the ideXlab platform.
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Preliminary Study on Converting Hybrid Poplar to High-Value Chemicals and Lignin Using Organosolv Ethanol Process
Industrial & Engineering Chemistry Research, 2010Co-Authors: Da-eun Kim, Xuejun PanAbstract:The Organosolv ethanol Process was adapted for converting hybrid poplar (Populus nigra L. × P. maximowiczii) into Organosolv lignin and saccharide-derived chemicals, such as levulinic acid (LA), hydroxymethylfurfural (HMF), and furfural. The effect of Process conditions (temperature, ethanol concentration, sulfuric acid dosage, and reaction time) on product yields was investigated using an experimental matrix designed with response surface methodology (RSM) and small Hartley composite design. The conditions ranged over 173−207 °C, 15−66 min, 2.3−5.7% H2SO4 (SA) on oven-dry wood (w/w), and 33−67% ethanol concentration (v/v). Results indicated that temperature, sulfuric acid loading, and their interaction had a significant effect on the yields of lignin and saccharide-derived chemicals. Comparative investigation of the Organosolv Process and acid Process indicated that ethanol not only enhanced the delignification and production of Organosolv lignin, but also improved the conversion yields of pentoses to fu...
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the bioconversion of mountain pine beetle killed lodgepole pine to fuel ethanol using the Organosolv Process
Biotechnology and Bioengineering, 2008Co-Authors: Xuejun Pan, Dan Xie, John N SaddlerAbstract:Lodgepole pine (Pinus contorta) killed by mountain pine beetle (Dendroctonus ponderosae) (BLP) was compared with healthy lodgepole pine (HLP) for bioconversion to ethanol and high-value co-products. The BLP and HLP chips were pretreated using an ethanol Organosolv Process at a variety of severities. It was shown that the BLP was easier to pretreat and delignify than were the HLP chips. The resulting pretreated BLP substrate had a lower residual lignin, lower degree of polymerization of cellulose, lower cellulose crystallinity, smaller fiber size and thereby a better enzymatic hydrolysability than did the HLP substrates. However, under the same conditions, the BLP showed lower substrate yield and cellulose recovery than did the HLP, which likely resulted from the excessive hydrolysis and subsequent decomposition of the cellulose and hemicellulose during the pretreatment. The BLP wood yielded more ethanol Organosolv lignin than was obtained with the HLP material. The HLP lignin had a lower molecular weight and narrower distribution than did the BLP lignin. It appears that the beetle killed LP is more receptive to Organosolv pretreatment other than a slightly lower recovery of carbohydrates.
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pretreatment of lodgepole pine killed by mountain pine beetle using the ethanol Organosolv Process fractionation and Process optimization
Industrial & Engineering Chemistry Research, 2007Co-Authors: Xuejun Pan, Dan Xie, Dexter Lam, John N SaddlerAbstract:Lodgepole pine (Pinus contorta) killed by mountain pine beetle (Dendroctonus ponderosae) (MPB-LPP) was evaluated for bioconversion to ethanol using the ethanol Organosolv Process. The pretreatment was optimized using an experimental matrix designed with response surface methodology. It was found that MPB-LPP was easy to pretreat and delignify, but gave low yields of substrate and carbohydrate as a result of excessive hydrolysis and subsequent decomposition of cellulose and hemicellulose during the pretreatment. The center-point conditions (170 °C, 60 min, 1.1% H2SO4 and 65% ethanol) were close to the optimum for the recovery of glucose and ethanol Organosolv lignin. At the center-point conditions, ∼75% of the cellulose present in the untreated wood was recovered in the substrate fraction, and approximately 79% of the lignin in the wood was recovered as ethanol Organosolv lignin (EOL). The combined recovery of carbohydrate in the substrate and water-soluble fractions was ∼83% glucose, ∼46% mannose, ∼53% xy...
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bioconversion of hybrid poplar to ethanol and co products using an Organosolv fractionation Process optimization of Process yields
Biotechnology and Bioengineering, 2006Co-Authors: Xuejun Pan, N R Gilkes, John F Kadla, Kendall Pye, Shiro Saka, David J Gregg, Katsunobu Ehara, Dan Xie, Dexter Lam, John N SaddlerAbstract:An Organosolv Process involving extraction with hot aqueous ethanol has been evaluated for bioconversion of hybrid poplar to ethanol. The Process resulted in fractionation of poplar chips into a cellulose-rich solids fraction, an ethanol Organosolv lignin (EOL) fraction, and a water-soluble fraction containing hemicellulosic sugars, sugar breakdown products, degraded lignin, and other components. The influence of four independent Process variables (temperature, time, catalyst dose, and ethanol concentration) on product yields was analyzed over a broad range using a small composite design and response surface methodology. Center point conditions for the composite design (180 degrees C, 60 min, 1.25% H(2)SO(4), and 60% ethanol), yielded a solids fraction containing approximately 88% of the cellulose present in the untreated poplar. Approximately 82% of the total cellulose in the untreated poplar was recovered as monomeric glucose after hydrolysis of the solids fraction for 24 h using a low enzyme loading (20 filter paper units of cellulase/g cellulose); approximately 85% was recovered after 48 h hydrolysis. Total recovery of xylose (soluble and insoluble) was equivalent to approximately 72% of the xylose present in untreated wood. Approximately 74% of the lignin in untreated wood was recovered as EOL. Other cooking conditions resulted in either similar or inferior product yields although the distribution of components between the various fractions differed markedly. Data analysis generated regression models that describe Process responses for any combination of the four variables.
Dan Xie - One of the best experts on this subject based on the ideXlab platform.
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the bioconversion of mountain pine beetle killed lodgepole pine to fuel ethanol using the Organosolv Process
Biotechnology and Bioengineering, 2008Co-Authors: Xuejun Pan, Dan Xie, John N SaddlerAbstract:Lodgepole pine (Pinus contorta) killed by mountain pine beetle (Dendroctonus ponderosae) (BLP) was compared with healthy lodgepole pine (HLP) for bioconversion to ethanol and high-value co-products. The BLP and HLP chips were pretreated using an ethanol Organosolv Process at a variety of severities. It was shown that the BLP was easier to pretreat and delignify than were the HLP chips. The resulting pretreated BLP substrate had a lower residual lignin, lower degree of polymerization of cellulose, lower cellulose crystallinity, smaller fiber size and thereby a better enzymatic hydrolysability than did the HLP substrates. However, under the same conditions, the BLP showed lower substrate yield and cellulose recovery than did the HLP, which likely resulted from the excessive hydrolysis and subsequent decomposition of the cellulose and hemicellulose during the pretreatment. The BLP wood yielded more ethanol Organosolv lignin than was obtained with the HLP material. The HLP lignin had a lower molecular weight and narrower distribution than did the BLP lignin. It appears that the beetle killed LP is more receptive to Organosolv pretreatment other than a slightly lower recovery of carbohydrates.
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pretreatment of lodgepole pine killed by mountain pine beetle using the ethanol Organosolv Process fractionation and Process optimization
Industrial & Engineering Chemistry Research, 2007Co-Authors: Xuejun Pan, Dan Xie, Dexter Lam, John N SaddlerAbstract:Lodgepole pine (Pinus contorta) killed by mountain pine beetle (Dendroctonus ponderosae) (MPB-LPP) was evaluated for bioconversion to ethanol using the ethanol Organosolv Process. The pretreatment was optimized using an experimental matrix designed with response surface methodology. It was found that MPB-LPP was easy to pretreat and delignify, but gave low yields of substrate and carbohydrate as a result of excessive hydrolysis and subsequent decomposition of cellulose and hemicellulose during the pretreatment. The center-point conditions (170 °C, 60 min, 1.1% H2SO4 and 65% ethanol) were close to the optimum for the recovery of glucose and ethanol Organosolv lignin. At the center-point conditions, ∼75% of the cellulose present in the untreated wood was recovered in the substrate fraction, and approximately 79% of the lignin in the wood was recovered as ethanol Organosolv lignin (EOL). The combined recovery of carbohydrate in the substrate and water-soluble fractions was ∼83% glucose, ∼46% mannose, ∼53% xy...
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bioconversion of hybrid poplar to ethanol and co products using an Organosolv fractionation Process optimization of Process yields
Biotechnology and Bioengineering, 2006Co-Authors: Xuejun Pan, N R Gilkes, John F Kadla, Kendall Pye, Shiro Saka, David J Gregg, Katsunobu Ehara, Dan Xie, Dexter Lam, John N SaddlerAbstract:An Organosolv Process involving extraction with hot aqueous ethanol has been evaluated for bioconversion of hybrid poplar to ethanol. The Process resulted in fractionation of poplar chips into a cellulose-rich solids fraction, an ethanol Organosolv lignin (EOL) fraction, and a water-soluble fraction containing hemicellulosic sugars, sugar breakdown products, degraded lignin, and other components. The influence of four independent Process variables (temperature, time, catalyst dose, and ethanol concentration) on product yields was analyzed over a broad range using a small composite design and response surface methodology. Center point conditions for the composite design (180 degrees C, 60 min, 1.25% H(2)SO(4), and 60% ethanol), yielded a solids fraction containing approximately 88% of the cellulose present in the untreated poplar. Approximately 82% of the total cellulose in the untreated poplar was recovered as monomeric glucose after hydrolysis of the solids fraction for 24 h using a low enzyme loading (20 filter paper units of cellulase/g cellulose); approximately 85% was recovered after 48 h hydrolysis. Total recovery of xylose (soluble and insoluble) was equivalent to approximately 72% of the xylose present in untreated wood. Approximately 74% of the lignin in untreated wood was recovered as EOL. Other cooking conditions resulted in either similar or inferior product yields although the distribution of components between the various fractions differed markedly. Data analysis generated regression models that describe Process responses for any combination of the four variables.
Arthur J Ragauskas - One of the best experts on this subject based on the ideXlab platform.
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economic analysis of an Organosolv Process for bioethanol production
Bioresources, 2014Co-Authors: Jesse Kautto, Arthur J Ragauskas, Matthew J. Realff, Tuomo KassiAbstract:In a previous paper, conceptual Process design, simulation, and mass and energy balances were presented for an Organosolv Process with a hardwood feed of 2350 metric tons (MT) per day and ethanol, lignin, furfural, and acetic acid production rates of 459, 310, 6.6, and 30.3 MT/day, respectively. In this paper, the investment and operating costs of the Process and the minimum ethanol selling price (MESP) to make the Process economically feasible were estimated. The total capital investment of the plant was approximately 720 million USD. Lignin price was found to affect the MESP considerably. With a base case lignin price of 450 USD/MT, the MESP was approximately 3.1 USD per gallon (gal). Higher lignin price of 1000 USD/MT was required to equal the MESP with the December 2013 ethanol market price (2.0 USD/gal). In addition to lignin price, the MESP was found to be strongly affected by feedstock, enzyme, and investment costs. Variations in feedstock and investment costs affected the MESP by approximately 0.2 and 0.5 USD/gal, respectively. Changing the enzyme dosage and price from base case estimate of 5270 USD/MT and 0.02 g/g cellulose to more conservative 3700 USD/MT and 0.06 g/g cellulose, respectively, increased the MESP by 0.59 USD/gal.
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Design and simulation of an Organosolv Process for bioethanol production
Biomass Conversion and Biorefinery, 2013Co-Authors: Jesse Kautto, Matthew J. Realff, Arthur J RagauskasAbstract:Organosolv pulping can be used as a pretreatment step in bioethanol production. In addition to ethanol, Organosolv pulping allows for the production of a pure lignin product and other co-products. Based on publicly available information, conceptual Process design and simulation model were developed for an Organosolv Process. The simulation model was used to calculate the mass and energy balances and approximate fossil-based carbon dioxide (CO2) emissions for the Process. With a hardwood feed of 2,350 dry metric tons (MT) per day, 459 MT/day (53.9 million gallons per year) of ethanol was produced. This corresponded to a carbohydrate to ethanol conversion of 64 %. The production rates of lignin, furfural, and acetic acid were 310, 6.6, and 30.3 MT/day, respectively. The energy balance indicated that the Process was not energy self-sufficient. In addition to bark and organic residues combusted to produce energy, external fuel (natural gas) was needed to cover the steam demand. This was largely due to the energy consumed in recovering the solvent. Compared to a dilute acid bioethanol Process, the Organosolv Process was estimated to consume 34 % more energy. Allocating all emissions from natural gas combustion to the produced ethanol led to fossil CO2 emissions of 13.5 g per megajoule (MJ) of ethanol. The total fossil CO2 emissions of the Process, including also feedstock transportation and other less significant emission sources, would almost certainly not exceed the US Renewable Fuel Standard threshold limit (36.5 g CO2/MJ ethanol).
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dilute sulphuric acid and ethanol Organosolv pretreatment of miscanthus x giganteus
2010Co-Authors: Nicolas Brosse, Poulomi Sannigrahi, Roland El Hage, Arthur J RagauskasAbstract:Three Processes for the pretreatment of Miscanthus x Giganteus were compared, namely, dilute sulphuric acid treatment, an ethanol Organosolv treatment and a two-step protocol involving a presoaking step prior to the ethanol Organosolv treatment. The pretreatment assays were evaluated and compared on the basis of their Combined Severity factors. It was shown that the Organosolv Processes permitted an efficient removal of both lignin and hemicelluloses from the solid residue. A presoaking step prior to an Organosolv Process performed at low severity permitted to enhance the removal of lignin and hemicelluloses and the recovery of hemicellulose sugars.
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Pretreatment of Miscanthus x giganteus Using the Ethanol Organosolv Process for Ethanol Production
Industrial & Engineering Chemistry Research, 2009Co-Authors: Nicolas Brosse, Poulomi Sannigrahi, Arthur J RagauskasAbstract:A two-step procedure involving a dilute-acid presoaking step and an aqueous-ethanol Organosolv treatment has been evaluated and optimized for the conversion of Miscanthus x giganteus (MxG). This Process allowed for the efficient fractionation of the raw material into a cellulose-rich residue, an ethanol Organosolv lignin fraction, and a water-soluble fraction mainly containing hemicellulose sugars. It was found that the presoaking step not only allowed a better recovery of xylans, but also enhanced the dissolution of lignin in the aqueous ethanol and the digestibility of the remaining cellulose by enzymes. The optimized conditions yielded a solid residue containing about 95% of the initial glucans, from which 98% was recovered after 48 h of enzymatic hydrolysis. In addition, 71% of the lignin was recovered as ethanol Organosolv lignin (EOL), and the recovery of the xylans was equivalent to 73% of the xylose present in the raw Miscanthus.
José A. Teixeira - One of the best experts on this subject based on the ideXlab platform.
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Valorization of Eucalyptus nitens bark by Organosolv pretreatment for the production of advanced biofuels
Industrial Crops and Products, 2019Co-Authors: Antonio Larramendi, Remedios Yáñez, Ángeles Cancela, Ángel Sánchez, José A. Teixeira, Lucília DominguesAbstract:Abstract The biofuels production from alternative and renewable raw materials is mandatory to achieve sustainable growth based on a bioeconomy. Eucalyptus bark is a waste generated during the chemical manufacturing of Eucalyptus pulp that can be used as an alternative source of biomass, suitable for the production of biofuels. In this work, Eucalyptus nitens bark (ENB) was fractionated by Organosolv treatment for ethanol production. For that, a Doehlert experimental design was carried out to evaluate the dependent variables: temperature (170–200 °C), time (30–90 min) and ethanol-water percentage (50–80 %) on delignification of Eucalyptus bark. Organosolv Process was suitable for the fractionation of E. nitens bark. After treatment, 74–93 % of glucan was recovered and 25–52 % of delignification was achieved. Delignified ENB was subjected to simultaneous saccharification and fermentation Process for bioethanol production. The results showed that the variables temperature and time of Organosolv Process had significant influence on ethanol production. The Organosolv pretreatment improved the ethanol yield from 32 to 99%. This work shows a suitable Process for the valorization of Eucalyptus bark into bioethanol.
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kinetic modeling of enzymatic saccharification using wheat straw pretreated under autohydrolysis and Organosolv Process
Industrial Crops and Products, 2012Co-Authors: Hector A Ruiz, A A Vicente, José A. TeixeiraAbstract:The enzymatic saccharification kinetics of untreated wheat straw, pretreated solids obtained by a sequence of autohydrolysis (solubilization of hemicellulose) and Organosolv (solubilization of lignin) were studied together with two pure cellulose model substrates, filter paper and Avicel. Two kinetic models for glucose production were compared and its kinetic constants calculated. According to the obtained results, enzymatic saccharification of the autohydrolysis pretreated solids (APS) proved to be more effective than when the Organosolv pretreated solids (OPS) were used. The maximum extent of the enzymatic conversion of cellulose to glucose was 90.88% and 64.04%, for APS and OPS respectively, at 96 h. This result was probably due to an increase in accessible area for APS and a possible inhibition by phenolic acids deposited on the surface of OPS, acting as a barrier for enzymatic saccharification. Initial saccharification rate for APS and OPS was 0.47 g/(L h) and 0.34 g/(L h), respectively. Models based on first and second order cellulase deactivation kinetics satisfactory predicted the behavior of glucose production, however the second order model had a higher accuracy than the first order one. Visualization of structural modification induced by enzymatic saccharification at 12 h for the pretreated solids was done using scanning electron microscopy.
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development and characterization of an environmentally friendly Process sequence autohydrolysis and Organosolv for wheat straw delignification
Applied Biochemistry and Biotechnology, 2011Co-Authors: Hector A Ruiz, Denise S Ruzene, Daniel Pereira Da Silva, Fernando Macieira F Da Silva, A A Vicente, José A. TeixeiraAbstract:The present work describes the delignification of wheat straw through an environmentally friendly Process resulting from sequential application of autohydrolysis and Organosolv Processes. Wheat straw autohydrolysis was performed at 180°C during 30 min with a liquid–solid ratio of 10 (v/w); under these conditions, a solubilization of 44% of the original xylan, with 78% of sugars as xylooligosaccharides of the sum of sugars solubilized in the autohydrolysis liquors generated by the hemicellulose fraction hydrolysis. The corresponding solid fraction enrichment with 63.7% of glucan and 7.55% of residual xylan was treated with a 40% ethanol and 0.1% NaOH aqueous solution at a liquid–solid ratio of 10 (v/w), with the best results obtained at 180°C during 20 min. The highest lignin recovery, measured by acid precipitation of the extracted lignin, was 3.25 g/100 ml. The lignin obtained by precipitation was characterized by FTIR, and the crystallinity indexes from the native cellulose, the cellulose recovered after autohydrolysis, and the cellulose obtained after applying the Organosolv Process were obtained by X-ray diffraction, returning values of 21.32%, 55.17%, and 53.59%, respectively. Visualization of the fibers was done for all the Processing steps using scanning electron microscopy.
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carboxymethylcellulose obtained by ethanol water Organosolv Process under acid conditions
Applied Biochemistry and Biotechnology, 2007Co-Authors: Denise S Ruzene, José A. Teixeira, Adilson R Gonçalves, Maria T Pessoa De AmorimAbstract:Sugar cane bagasse pulps were obtained by ethanol/water Organosolv Process under acid and alkaline conditions. The best condition of acid pulping for the sugarcane bagasse was 0.02 mol/L sulfuric acid at 160°C, for 1 h, whereas the best condition for alkaline pulping was 5% sodium hydroxide (base pulp) at 160°C, for 3 h. For the residual lignin removal, the acid and alkaline pulps were submitted to a chemical bleaching using sodium chlorite. Pulps under acid and alkaline conditions bleached with sodium chlorite presented viscosities of 3.6 and 7.8 mPa·s, respectively, and μ-kappa numbers of 1.1 and 2.4, respectively. The pulp under acid condition, bleached with sodium chlorite was used to obtain carboxymethylcellulose (CMC). CMC yield was 35% (pulp based), showing mass gain after the carboxymethylation reaction corresponding to 23.6% of substitution or 0.70 groups −CH2 COONa per unit of glucose residue. The infrared spectra showed the CMC characteristic bands and by the infrared technique it was possible to obtain a substitution degree (0.63), similar to the substitution degree calculated by mass gain (0.70).